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Title: GitHub - objects/How-To-Secure-A-Linux-Server: An evolving how-to guide for securing a Linux server.

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Description: An evolving how-to guide for securing a Linux server. - objects/How-To-Secure-A-Linux-Server

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Other Important Noteshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#other-important-notes
Using Ansible Playbooks to secure your Linux Serverhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#using-ansible-playbooks-to-secure-your-linux-server
The SSH Serverhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#the-ssh-server
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https://security.utexas.edu/os-hardening-checklist/linux-7https://security.utexas.edu/os-hardening-checklist/linux-7
https://cloudpro.zone/index.php/2018/01/18/debian-9-3-server-setup-guide-part-1/https://cloudpro.zone/index.php/2018/01/18/debian-9-3-server-setup-guide-part-1/
https://blog.vigilcode.com/2011/04/ubuntu-server-initial-security-quick-secure-setup-part-i/https://blog.vigilcode.com/2011/04/ubuntu-server-initial-security-quick-secure-setup-part-i/
https://www.tldp.org/LDP/sag/html/index.htmlhttps://www.tldp.org/LDP/sag/html/index.html
https://seifried.org/lasg/https://seifried.org/lasg/
https://news.ycombinator.com/item?id=19178964https://news.ycombinator.com/item?id=19178964
https://wiki.archlinux.org/index.php/Securityhttps://wiki.archlinux.org/index.php/Security
https://securecompliance.co/linux-server-hardening-checklist/https://securecompliance.co/linux-server-hardening-checklist/
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https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#to-do--to-add
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https://en.wikipedia.org/wiki/Security-Enhanced_Linuxhttps://en.wikipedia.org/wiki/Security-Enhanced_Linux
https://linuxtechlab.com/beginners-guide-to-selinux/https://linuxtechlab.com/beginners-guide-to-selinux/
https://linuxtechlab.com/replicate-selinux-policies-among-linux-machines/https://linuxtechlab.com/replicate-selinux-policies-among-linux-machines/
https://teamignition.us/how-to-stop-being-a-scrub-and-learn-to-use-selinux.htmlhttps://teamignition.us/how-to-stop-being-a-scrub-and-learn-to-use-selinux.html
https://wiki.archlinux.org/index.php/AppArmorhttps://wiki.archlinux.org/index.php/AppArmor
https://security.stackexchange.com/questions/29378/comparison-between-apparmor-and-selinuxhttps://security.stackexchange.com/questions/29378/comparison-between-apparmor-and-selinux
http://www.insanitybit.com/2012/06/01/why-i-like-apparmor-more-than-selinux-5/http://www.insanitybit.com/2012/06/01/why-i-like-apparmor-more-than-selinux-5/
http://www.chkrootkit.org/http://www.chkrootkit.org/
http://rkhunter.sourceforge.net/http://rkhunter.sourceforge.net/
https://www.cyberciti.biz/faq/howto-check-linux-rootkist-with-detectors-software/https://www.cyberciti.biz/faq/howto-check-linux-rootkist-with-detectors-software/
https://www.tecmint.com/install-rootkit-hunter-scan-for-rootkits-backdoors-in-linux/https://www.tecmint.com/install-rootkit-hunter-scan-for-rootkits-backdoors-in-linux/
https://news.ycombinator.com/item?id=19178681https://news.ycombinator.com/item?id=19178681
https://learn.cisecurity.org/cis-cat-landing-pagehttps://learn.cisecurity.org/cis-cat-landing-page
https://blog.sleeplessbeastie.eu/2015/03/02/how-to-verify-installed-packages/https://blog.sleeplessbeastie.eu/2015/03/02/how-to-verify-installed-packages/
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#guide-overview
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#about-this-guide
install Linuxhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#installing-linux
https://linuxjourney.com/https://linuxjourney.com/
Linux distribution agnostichttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#picking-a-linux-distribution
text editorhttps://notepad-plus-plus.org/
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#my-use-case
NAThttps://en.wikipedia.org/wiki/Network_address_translation
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
INIhttps://en.wikipedia.org/wiki/INI_file
favoritehttps://en.wikipedia.org/wiki/Vi
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#contributing
GitHubhttp://www.github.com
new issuehttps://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/new
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#before-you-start
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#identify-your-principles
threat modelhttps://en.wikipedia.org/wiki/Threat_model
disabled root loginhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#disable-root-login
password protected GRUBhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#password-protect-grub
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#picking-a-linux-distribution
any distributionhttps://distrowatch.com/
unattended upgradehttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#automatic-security-updates-and-alerts
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#installing-linux
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#prepost-installation-requirements
Gmail and Exim4 As MTA With Implicit TLShttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#gmail-and-exim4-as-mta-with-implicit-tls
CIS Benchmarkshttps://www.cisecurity.org/cis-benchmarks/
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#other-important-notes
contact mehttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#contacting-me
Debian based distributionshttps://www.debian.org/derivatives/
providehttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#contributing
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#using-ansible-playbooks-to-secure-your-linux-server
How To Secure A Linux Server With Ansiblehttps://github.com/moltenbit/How-To-Secure-A-Linux-Server-With-Ansible
Ansiblehttps://docs.ansible.com/ansible/latest/installation_guide/intro_installation.html
How To Secure A Linux Server With Ansiblehttps://github.com/moltenbit/How-To-Secure-A-Linux-Server-With-Ansible
Create SSH-Public/Private-Keyshttps://github.com/imthenachoman/How-To-Secure-A-Linux-Server#ssh-publicprivate-keys
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#the-ssh-server
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#important-note-before-you-make-ssh-changes
Sonnenbrandhttps://github.com/Sonnenbrand
ideahttps://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/56
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#ssh-publicprivate-keys
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works
ssh-copy-idhttps://www.ssh.com/ssh/copy-id
Digital Oceanhttps://www.digitalocean.com/community/tutorials/understanding-the-ssh-encryption-and-connection-process
PasswordAuthentication no in /etc/ssh/sshd_confighttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#PasswordAuthentication
https://linux-audit.com/https://linux-audit.com/using-ed25519-openssh-keys-instead-of-dsa-rsa-ecdsa/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references
https://www.ssh.com/ssh/public-key-authenticationhttps://www.ssh.com/ssh/public-key-authentication
https://help.ubuntu.com/community/SSH/OpenSSH/Keyshttps://help.ubuntu.com/community/SSH/OpenSSH/Keys
https://linux-audit.com/using-ed25519-openssh-keys-instead-of-dsa-rsa-ecdsa/https://linux-audit.com/using-ed25519-openssh-keys-instead-of-dsa-rsa-ecdsa/
https://www.digitalocean.com/community/tutorials/understanding-the-ssh-encryption-and-connection-processhttps://www.digitalocean.com/community/tutorials/understanding-the-ssh-encryption-and-connection-process
https://wiki.archlinux.org/index.php/SSH_Keyshttps://wiki.archlinux.org/index.php/SSH_Keys
https://www.ssh.com/ssh/copy-idhttps://www.ssh.com/ssh/copy-id
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps
Ed25519https://linux-audit.com/using-ed25519-openssh-keys-instead-of-dsa-rsa-ecdsa/
MIMhttps://en.wikipedia.org/wiki/Man-in-the-middle_attack
perform any tasks specific to your setuphttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#prepost-installation-requirements
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#create-ssh-group-for-allowgroups
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-1
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-1
AllowGroups optionhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#AllowGroups
/etc/ssh/sshd_confighttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#secure-etcsshsshd_config
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-1
Secure /etc/ssh/sshd_confighttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#secure-etcsshsshd_config
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-1
Secure /etc/ssh/sshd_confighttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#secure-etcsshsshd_config
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-1
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-1
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#secure-etcsshsshd_config
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-2
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-2
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-2
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-2
Create SSH Group For AllowGroupshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#create-ssh-group-for-allowgroups
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-2
https://infosec.mozilla.org/guidelines/openssh#modern-openssh-67https://infosec.mozilla.org/guidelines/openssh#modern-openssh-67
https://linux-audit.com/audit-and-harden-your-ssh-configuration/https://linux-audit.com/audit-and-harden-your-ssh-configuration/
https://www.ssh.com/ssh/sshd_config/https://www.ssh.com/ssh/sshd_config/
https://www.techbrown.com/harden-ssh-secure-linux-vps-server/https://www.techbrown.com/harden-ssh-secure-linux-vps-server/
http://web.archive.org/web/20200413100933/https://www.techbrown.com/harden-ssh-secure-linux-vps-server/http://web.archive.org/web/20200413100933/https://www.techbrown.com/harden-ssh-secure-linux-vps-server/
https://serverfault.com/questions/660160/openssh-difference-between-internal-sftp-and-sftp-server/660325https://serverfault.com/questions/660160/openssh-difference-between-internal-sftp-and-sftp-server/660325
than0shttps://github.com/than0s
how to find duplicate settingshttps://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/38
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-2
Issue #1https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/1
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#remove-short-diffie-hellman-keys
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-3
Mozilla's OpenSSH guidelines for OpenSSH 6.7+https://infosec.mozilla.org/guidelines/openssh#modern-openssh-67
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-3
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-3
https://infosec.mozilla.org/guidelines/openssh#modern-openssh-67https://infosec.mozilla.org/guidelines/openssh#modern-openssh-67
https://infosec.mozilla.org/guidelines/key_managementhttps://infosec.mozilla.org/guidelines/key_management
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-3
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#2famfa-for-ssh
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-4
Fail2banhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#fail2ban-application-intrusion-detection-and-prevention
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-not
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-3
https://en.wikipedia.org/wiki/Linux_PAMhttps://en.wikipedia.org/wiki/Linux_PAM
TOTPhttps://en.wikipedia.org/wiki/Time-based_One-time_Password_algorithm
https://fastmail.blog/2016/07/22/how-totp-authenticator-apps-work/https://fastmail.blog/2016/07/22/how-totp-authenticator-apps-work/
https://jemurai.com/2018/10/11/how-it-works-totp-based-mfa/https://jemurai.com/2018/10/11/how-it-works-totp-based-mfa/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-4
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-3
google-authenticator-libpamhttps://github.com/google/google-authenticator-libpam
SSH public/private keyshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#ssh-publicprivate-keys
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-4
https://github.com/google/google-authenticator-libpamhttps://github.com/google/google-authenticator-libpam
https://en.wikipedia.org/wiki/Linux_PAMhttps://en.wikipedia.org/wiki/Linux_PAM
https://en.wikipedia.org/wiki/Time-based_One-time_Password_algorithmhttps://en.wikipedia.org/wiki/Time-based_One-time_Password_algorithm
https://fastmail.blog/2016/07/22/how-totp-authenticator-apps-work/https://fastmail.blog/2016/07/22/how-totp-authenticator-apps-work/
https://jemurai.com/2018/10/11/how-it-works-totp-based-mfa/https://jemurai.com/2018/10/11/how-it-works-totp-based-mfa/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-4
herehttps://github.com/google/google-authenticator-libpam/blob/master/README.md#nullok
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#the-basics
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#limit-who-can-use-sudo
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imthenachoman#39https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/39
sbrlhttps://github.com/sbrl
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-5
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#limit-who-can-use-su
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https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-6
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olavimhttps://github.com/olavim
this ideahttps://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/41
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-6
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#run-applications-in-a-sandbox-with-firejail
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https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-6
FireJailhttps://firejail.wordpress.com/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-7
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#ntp-client
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-8
global NTP servershttps://en.wikipedia.org/wiki/Network_Time_Protocol
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-4
https://www.pool.ntp.org/en/https://www.pool.ntp.org/en/
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https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-7
https://cloudpro.zone/index.php/2018/01/27/debian-9-3-server-setup-guide-part-4/https://cloudpro.zone/index.php/2018/01/27/debian-9-3-server-setup-guide-part-4/
https://en.wikipedia.org/wiki/Network_Time_Protocolhttps://en.wikipedia.org/wiki/Network_Time_Protocol
https://www.pool.ntp.org/en/https://www.pool.ntp.org/en/
https://serverfault.com/questions/957302/securing-hardening-ntp-client-on-linux-servers-config-file/957450#957450https://serverfault.com/questions/957302/securing-hardening-ntp-client-on-linux-servers-config-file/957450#957450
https://tf.nist.gov/tf-cgi/servers.cgihttps://tf.nist.gov/tf-cgi/servers.cgi
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-8
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#securing-proc
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-9
https://linux-audit.com/linux-system-hardening-adding-hidepid-to-proc/https://linux-audit.com/linux-system-hardening-adding-hidepid-to-proc/
imthenachoman#37https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/37
nlgrangerhttps://github.com/nlgranger
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https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-8
https://linux-audit.com/linux-system-hardening-adding-hidepid-to-proc/https://linux-audit.com/linux-system-hardening-adding-hidepid-to-proc/
https://likegeeks.com/secure-linux-server-hardening-best-practices/#Hardening-proc-Directoryhttps://likegeeks.com/secure-linux-server-hardening-best-practices/#Hardening-proc-Directory
https://www.cyberciti.biz/faq/linux-hide-processes-from-other-users/https://www.cyberciti.biz/faq/linux-hide-processes-from-other-users/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-9
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#force-accounts-to-use-secure-passwords
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-10
pwqualityhttps://linux.die.net/man/5/pwquality.conf
pam_pwqualityhttps://linux.die.net/man/8/pam_pwquality
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-5
https://en.wikipedia.org/wiki/Linux_PAMhttps://en.wikipedia.org/wiki/Linux_PAM
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https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-10
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#automatic-security-updates-and-alerts
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https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-11
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#debian-based-systems
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-6
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-9
https://wiki.debian.org/UnattendedUpgradeshttps://wiki.debian.org/UnattendedUpgrades
https://debian-handbook.info/browse/stable/sect.regular-upgrades.htmlhttps://debian-handbook.info/browse/stable/sect.regular-upgrades.html
https://blog.sleeplessbeastie.eu/2015/01/02/how-to-perform-unattended-upgrades/https://blog.sleeplessbeastie.eu/2015/01/02/how-to-perform-unattended-upgrades/
https://www.vultr.com/docs/how-to-set-up-unattended-upgrades-on-debian-9-stretchhttps://www.vultr.com/docs/how-to-set-up-unattended-upgrades-on-debian-9-stretch
https://github.com/mvo5/unattended-upgradeshttps://github.com/mvo5/unattended-upgrades
https://wiki.debian.org/UnattendedUpgrades#apt-listchangeshttps://wiki.debian.org/UnattendedUpgrades#apt-listchanges
https://www.cyberciti.biz/faq/apt-get-apticron-send-email-upgrades-available/https://www.cyberciti.biz/faq/apt-get-apticron-send-email-upgrades-available/
https://www.unixmen.com/how-to-get-email-notifications-for-new-updates-on-debianubuntu/https://www.unixmen.com/how-to-get-email-notifications-for-new-updates-on-debianubuntu/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-11
https://github.com/mvo5/unattended-upgradeshttps://github.com/mvo5/unattended-upgrades
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#more-secure-random-entropy-pool-wip
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-12
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-7
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-12
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-10
brannemanhttps://github.com/branneman
issue #33https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/33
https://hackaday.com/2017/11/02/what-is-entropy-and-how-do-i-get-more-of-it/https://hackaday.com/2017/11/02/what-is-entropy-and-how-do-i-get-more-of-it/
https://www.2uo.de/myths-about-urandomhttps://www.2uo.de/myths-about-urandom
https://www.gnu.org/software/hurd/user/tlecarrour/rng-tools.htmlhttps://www.gnu.org/software/hurd/user/tlecarrour/rng-tools.html
https://wiki.archlinux.org/index.php/Rng-toolshttps://wiki.archlinux.org/index.php/Rng-tools
https://www.howtoforge.com/helping-the-random-number-generator-to-gain-enough-entropy-with-rng-tools-debian-lennyhttps://www.howtoforge.com/helping-the-random-number-generator-to-gain-enough-entropy-with-rng-tools-debian-lenny
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/security_guide/sect-security_guide-encryption-using_the_random_number_generatorhttps://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/security_guide/sect-security_guide-encryption-using_the_random_number_generator
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-12
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/security_guide/sect-security_guide-encryption-using_the_random_number_generatorhttps://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/security_guide/sect-security_guide-encryption-using_the_random_number_generator
https://wiki.archlinux.org/index.php/Rng-toolshttps://wiki.archlinux.org/index.php/Rng-tools
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#add-panicsecondaryfake-password-login-security-system
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-13
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-8
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-13
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-11
nuvioushttps://github.com/nuvious/pam-duress
hellresistorhttps://gist.github.com/hellresistor/a4c542415a2d437e21afc235260d2366
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-13
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#the-network
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#firewall-with-ufw-uncomplicated-firewall
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-14
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-9
iptableshttps://en.wikipedia.org/wiki/Iptables
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-14
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-6
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-12
https://launchpad.net/ufwhttps://launchpad.net/ufw
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-14
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#default-applications
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#custom-application
Plexhttps://support.plex.tv/articles/201543147-what-network-ports-do-i-need-to-allow-through-my-firewall/
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#iptables-intrusion-detection-and-prevention-with-psad
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-15
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-10
FINESEChttps://serverfault.com/users/143961/finesec
https://serverfault.com/https://serverfault.com/
https://serverfault.com/a/447604/289829https://serverfault.com/a/447604/289829
UFWhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#ufw-uncomplicated-firewall
netsonhttps://gist.github.com/netson
https://gist.github.com/netson/c45b2dc4e835761fbccchttps://gist.github.com/netson/c45b2dc4e835761fbccc
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-13
http://www.cipherdyne.org/psad/http://www.cipherdyne.org/psad/
http://www.cipherdyne.org/psad/docs/config.htmlhttp://www.cipherdyne.org/psad/docs/config.html
https://www.thefanclub.co.za/how-to/how-install-psad-intrusion-detection-ubuntu-1204-lts-serverhttps://www.thefanclub.co.za/how-to/how-install-psad-intrusion-detection-ubuntu-1204-lts-server
https://serverfault.com/a/447604/289829https://serverfault.com/a/447604/289829
https://serverfault.com/a/770424/289829https://serverfault.com/a/770424/289829
https://gist.github.com/netson/c45b2dc4e835761fbccchttps://gist.github.com/netson/c45b2dc4e835761fbccc
moltenbithttps://github.com/moltenbit
#61https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/61
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-15
EMAIL_ADDRESSEShttp://www.cipherdyne.org/psad/docs/config.html#EMAIL_ADDRESSES
ENABLE_AUTO_IDShttp://www.cipherdyne.org/psad/docs/config.html#ENABLE_AUTO_IDS
http://www.cipherdyne.org/psad/docs/config.htmlhttp://www.cipherdyne.org/psad/docs/config.html
seperating iptables logs to their own filehttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#ns-separate-iptables-log-file
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#application-intrusion-detection-and-prevention-with-fail2ban
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-16
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-11
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-15
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-7
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-14
https://www.fail2ban.org/https://www.fail2ban.org/
https://blog.vigilcode.com/2011/05/ufw-with-fail2ban-quick-secure-setup-part-ii/https://blog.vigilcode.com/2011/05/ufw-with-fail2ban-quick-secure-setup-part-ii/
https://dodwell.us/security/ufw-fail2ban-portscan.htmlhttps://dodwell.us/security/ufw-fail2ban-portscan.html
https://www.howtoforge.com/community/threads/fail2ban-and-ufw-on-debian.77261/https://www.howtoforge.com/community/threads/fail2ban-and-ufw-on-debian.77261/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-16
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#custom-jails
contributehttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#contributing
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#unban-an-ip
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#application-intrusion-detection-and-prevention-with-crowdsec
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-17
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-12
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-16
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-8
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-15
https://www.crowdsec.net/https://www.crowdsec.net/
Read how CrowdSec curates the Community Blocklisthttps://www.crowdsec.net/our-data
Read what threat intelligence is shared with CrowdSechttps://docs.crowdsec.net/docs/next/central_api/intro#signal-meta-data
https://docs.crowdsec.net/https://docs.crowdsec.net/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-17
herehttps://docs.crowdsec.net/u/getting_started/installation/linux
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#unban-an-ip-1
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#the-auditing
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#filefolder-integrity-monitoring-with-aide-wip
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-18
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-13
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-17
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-16
https://aide.github.io/https://aide.github.io/
https://www.hiroom2.com/2017/06/09/debian-8-file-integrity-check-with-aide/https://www.hiroom2.com/2017/06/09/debian-8-file-integrity-check-with-aide/
https://blog.rapid7.com/2017/06/30/how-to-install-and-configure-aide-on-ubuntu-linux/https://blog.rapid7.com/2017/06/30/how-to-install-and-configure-aide-on-ubuntu-linux/
https://www.stephenrlang.com/2016/03/using-aide-for-file-integrity-monitoring-fim-on-ubuntu/https://www.stephenrlang.com/2016/03/using-aide-for-file-integrity-monitoring-fim-on-ubuntu/
https://www.howtoforge.com/how-to-configure-the-aide-advanced-intrusion-detection-environment-file-integrity-scanner-for-your-websitehttps://www.howtoforge.com/how-to-configure-the-aide-advanced-intrusion-detection-environment-file-integrity-scanner-for-your-website
https://www.tecmint.com/check-integrity-of-file-and-directory-using-aide-in-linux/https://www.tecmint.com/check-integrity-of-file-and-directory-using-aide-in-linux/
https://www.cyberciti.biz/faq/debian-ubuntu-linux-software-integrity-checking-with-aide/https://www.cyberciti.biz/faq/debian-ubuntu-linux-software-integrity-checking-with-aide/
imthenachoman#83https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/83
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-18
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#updating-the-database
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#anti-virus-scanning-with-clamav-wip
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-19
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-14
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-18
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-9
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-17
https://www.clamav.net/documents/installation-on-debian-and-ubuntu-linux-distributionshttps://www.clamav.net/documents/installation-on-debian-and-ubuntu-linux-distributions
https://wiki.debian.org/ClamAVhttps://wiki.debian.org/ClamAV
https://www.osradar.com/install-clamav-debian-9-ubuntu-18/https://www.osradar.com/install-clamav-debian-9-ubuntu-18/
https://www.lisenet.com/2014/automate-clamav-to-perform-daily-system-scan-and-send-email-notifications-on-linux/https://www.lisenet.com/2014/automate-clamav-to-perform-daily-system-scan-and-send-email-notifications-on-linux/
https://www.howtoforge.com/tutorial/configure-clamav-to-scan-and-notify-virus-and-malware/https://www.howtoforge.com/tutorial/configure-clamav-to-scan-and-notify-virus-and-malware/
https://serverfault.com/questions/741299/is-there-a-way-to-keep-clamav-updated-on-debian-8https://serverfault.com/questions/741299/is-there-a-way-to-keep-clamav-updated-on-debian-8
https://askubuntu.com/questions/250290/how-do-i-scan-for-viruses-with-clamavhttps://askubuntu.com/questions/250290/how-do-i-scan-for-viruses-with-clamav
https://ngothang.com/how-to-install-clamav-and-configure-daily-scanning-on-centos/https://ngothang.com/how-to-install-clamav-and-configure-daily-scanning-on-centos/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-19
https://serverfault.com/questions/741299/is-there-a-way-to-keep-clamav-updated-on-debian-8https://serverfault.com/questions/741299/is-there-a-way-to-keep-clamav-updated-on-debian-8
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#scanning-filesfolders
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#rootkit-detection-with-rkhunter-wip
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-20
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-15
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-19
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-18
http://rkhunter.sourceforge.net/http://rkhunter.sourceforge.net/
https://www.cyberciti.biz/faq/howto-check-linux-rootkist-with-detectors-software/https://www.cyberciti.biz/faq/howto-check-linux-rootkist-with-detectors-software/
https://www.tecmint.com/install-rootkit-hunter-scan-for-rootkits-backdoors-in-linux/https://www.tecmint.com/install-rootkit-hunter-scan-for-rootkits-backdoors-in-linux/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-20
https://www.tecmint.com/install-rootkit-hunter-scan-for-rootkits-backdoors-in-linux/https://www.tecmint.com/install-rootkit-hunter-scan-for-rootkits-backdoors-in-linux/
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#rootkit-detection-with-chrootkit-wip
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-21
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-16
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-20
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-19
http://www.chkrootkit.org/http://www.chkrootkit.org/
https://www.cyberciti.biz/faq/howto-check-linux-rootkist-with-detectors-software/https://www.cyberciti.biz/faq/howto-check-linux-rootkist-with-detectors-software/
https://askubuntu.com/questions/258658/eth0-packet-sniffer-sbin-dhclienthttps://askubuntu.com/questions/258658/eth0-packet-sniffer-sbin-dhclient
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-21
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#logwatch---system-log-analyzer-and-reporter
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-22
logwatchhttps://sourceforge.net/projects/logwatch/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-17
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-21
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-10
https://www.badpenguin.org/configure-logwatch-for-weekly-email-and-html-output-formathttps://www.badpenguin.org/configure-logwatch-for-weekly-email-and-html-output-format
https://blog.dhampir.no/content/exim4-line-length-in-debian-stretch-mail-delivery-failed-returning-message-to-senderhttps://blog.dhampir.no/content/exim4-line-length-in-debian-stretch-mail-delivery-failed-returning-message-to-sender
issue #29https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/29
Gmail and Exim4 As MTA With Implicit TLShttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#gmail-and-exim4-as-mta-with-implicit-tls
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-20
amacheemahttps://github.com/amacheema
issue #29https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/29
https://sourceforge.net/projects/logwatch/https://sourceforge.net/projects/logwatch/
https://www.digitalocean.com/community/tutorials/how-to-install-and-use-logwatch-log-analyzer-and-reporter-on-a-vpshttps://www.digitalocean.com/community/tutorials/how-to-install-and-use-logwatch-log-analyzer-and-reporter-on-a-vps
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-22
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
https://blog.dhampir.no/content/exim4-line-length-in-debian-stretch-mail-delivery-failed-returning-message-to-senderhttps://blog.dhampir.no/content/exim4-line-length-in-debian-stretch-mail-delivery-failed-returning-message-to-sender
issue #29https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/29
Gmail and Exim4 As MTA With Implicit TLShttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#gmail-and-exim4-as-mta-with-implicit-tls
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#ss---seeing-ports-your-server-is-listening-on
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-23
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-22
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-21
https://www.reddit.com/r/linux/comments/arx7st/howtosecurealinuxserver_an_evolving_howto_guide/egrib6o/https://www.reddit.com/r/linux/comments/arx7st/howtosecurealinuxserver_an_evolving_howto_guide/egrib6o/
https://www.reddit.com/r/linux/comments/arx7st/howtosecurealinuxserver_an_evolving_howto_guide/egs1rev/https://www.reddit.com/r/linux/comments/arx7st/howtosecurealinuxserver_an_evolving_howto_guide/egs1rev/
https://www.tecmint.com/find-open-ports-in-linux/https://www.tecmint.com/find-open-ports-in-linux/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-23
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#lynis---linux-security-auditing
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-24
https://cisofy.com/lynis/https://cisofy.com/lynis/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-23
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-11
https://packages.cisofy.com/https://packages.cisofy.com/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-22
https://cisofy.com/documentation/lynis/get-started/https://cisofy.com/documentation/lynis/get-started/
https://packages.cisofy.com/community/#debian-ubuntuhttps://packages.cisofy.com/community/#debian-ubuntu
https://thelinuxcode.com/audit-lynis-ubuntu-server/https://thelinuxcode.com/audit-lynis-ubuntu-server/
https://www.vultr.com/docs/install-lynis-on-debian-8https://www.vultr.com/docs/install-lynis-on-debian-8
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-24
https://cisofy.com/lynis/#installationhttps://cisofy.com/lynis/#installation
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#ossec---host-intrusion-detection
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-25
https://github.com/ossec/ossec-hidshttps://github.com/ossec/ossec-hids
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-24
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-23
https://www.ossec.net/docs/https://www.ossec.net/docs/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-25
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#the-danger-zone
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#proceed-at-your-own-risk
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents-1
Linux Kernel sysctl Hardeninghttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#linux-kernel-sysctl-hardening
Password Protect GRUBhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#password-protect-grub
Disable Root Loginhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#disable-root-login
Change Default umaskhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#change-default-umask
Orphaned Softwarehttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#orphaned-software
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#linux-kernel-sysctl-hardening
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-26
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-not-2
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#disclaimer
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For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-12
documentation I can findhttps://github.com/torvalds/linux/tree/master/Documentation
let me knowhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#contacting-me
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-24
https://github.com/torvalds/linux/tree/master/Documentationhttps://github.com/torvalds/linux/tree/master/Documentation
https://www.cyberciti.biz/faq/linux-kernel-etcsysctl-conf-security-hardening/https://www.cyberciti.biz/faq/linux-kernel-etcsysctl-conf-security-hardening/
https://geektnt.com/sysctl-conf-hardening.htmlhttps://geektnt.com/sysctl-conf-hardening.html
https://linoxide.com/how-tos/linux-server-protection/https://linoxide.com/how-tos/linux-server-protection/
https://github.com/klaver/sysctl/blob/master/sysctl.confhttps://github.com/klaver/sysctl/blob/master/sysctl.conf
https://cloudpro.zone/index.php/2018/01/30/debian-9-3-server-setup-guide-part-5/https://cloudpro.zone/index.php/2018/01/30/debian-9-3-server-setup-guide-part-5/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-26
linux-kernel-sysctl-hardening.mdhttps://github.com/imthenachoman/How-To-Secure-A-Linux-Server/blob/master/linux-kernel-sysctl-hardening.md
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#password-protect-grub
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-27
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-not-3
some workhttps://www.cyberciti.biz/tips/howto-recovering-grub-boot-loader-password.html
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-25
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-13
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-25
https://selivan.github.io/2017/12/21/grub2-password-for-all-but-default-menu-entries.htmlhttps://selivan.github.io/2017/12/21/grub2-password-for-all-but-default-menu-entries.html
https://help.ubuntu.com/community/Grub2/Passwordshttps://help.ubuntu.com/community/Grub2/Passwords
https://computingforgeeks.com/how-to-protect-grub-with-password-on-debian-ubuntu-and-kali-linux/https://computingforgeeks.com/how-to-protect-grub-with-password-on-debian-ubuntu-and-kali-linux/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-27
Password-Based Key Derivation Function 2 (PBKDF2)https://en.wikipedia.org/wiki/PBKDF2
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#disable-root-login
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-28
configured properlyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#limit-who-can-use-sudo
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-not-4
suloginhttps://linux.die.net/man/8/sulogin
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-26
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-14
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-26
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=806852https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=806852
systemd/systemd#7115https://github.com/systemd/systemd/issues/7115
https://github.com/karelzak/util-linux/commit/7ff1162e67164cb4ece19dd809c26272461aa254https://github.com/karelzak/util-linux/commit/7ff1162e67164cb4ece19dd809c26272461aa254
systemd/systemd#11596https://github.com/systemd/systemd/issues/11596
https://www.reddit.com/r/selfhosted/comments/aoxd4l/new_guide_created_by_me_how_to_secure_a_linux/eg4rkfi/https://www.reddit.com/r/selfhosted/comments/aoxd4l/new_guide_created_by_me_how_to_secure_a_linux/eg4rkfi/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-28
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#change-default-umask
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-29
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-not-5
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#how-it-works-18
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-27
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-15
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-27
https://www.linuxnix.com/umask-define-linuxunix/https://www.linuxnix.com/umask-define-linuxunix/
https://serverfault.com/questions/818783/which-umask-is-more-secure-in-linux-022-or-027https://serverfault.com/questions/818783/which-umask-is-more-secure-in-linux-022-or-027
https://www.cyberciti.biz/tips/understanding-linux-unix-umask-value-usage.htmlhttps://www.cyberciti.biz/tips/understanding-linux-unix-umask-value-usage.html
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-29
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#orphaned-software
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-30
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#notes-16
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#debian-based-systems-1
deborphanhttp://freshmeat.sourceforge.net/projects/deborphan/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-not-6
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-30
Assuming you want to remove all of the packages deborphan findshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#orphaned-software-why-not
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#the-miscellaneous
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#the-simple-way-with-msmtp
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-31
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#gmail-and-exim4-as-mta-with-implicit-tls
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-32
previous version of this guidehttps://github.com/imthenachoman/How-To-Secure-A-Linux-Server/tree/cc5edcae1cf846dd250e76b121e721d836481d2f#configure-gmail-as-mta
issue #29https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/29
herehttps://blog.dhampir.no/content/exim4-line-length-in-debian-stretch-mail-delivery-failed-returning-message-to-sender
#106https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/106
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#goals-28
Gmailhttps://mail.google.com/
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-28
remyabelhttps://github.com/remyabel
issue #24https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/24
pull request #26https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/pull/26
https://wiki.debian.org/Eximhttps://wiki.debian.org/Exim
https://wiki.debian.org/GmailAndExim4https://wiki.debian.org/GmailAndExim4
https://www.exim.org/exim-html-current/doc/html/spec_html/ch-encrypted_smtp_connections_using_tlsssl.htmlhttps://www.exim.org/exim-html-current/doc/html/spec_html/ch-encrypted_smtp_connections_using_tlsssl.html
https://php.quicoto.com/setup-exim4-to-use-gmail-in-ubuntu/https://php.quicoto.com/setup-exim4-to-use-gmail-in-ubuntu/
https://www.fastmail.com/help/technical/ssltlsstarttls.htmlhttps://www.fastmail.com/help/technical/ssltlsstarttls.html
issue #29https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/29
https://blog.dhampir.no/content/exim4-line-length-in-debian-stretch-mail-delivery-failed-returning-message-to-senderhttps://blog.dhampir.no/content/exim4-line-length-in-debian-stretch-mail-delivery-failed-returning-message-to-sender
imthenachoman#106https://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/106
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-31
Let's Encrypthttps://letsencrypt.org/
fix exim4's long lines issuehttps://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/29
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
UFWhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#ufw-uncomplicated-firewall
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#separate-iptables-log-file
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#why-33
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#references-29
https://blog.shadypixel.com/log-iptables-messages-to-a-separate-file-with-rsyslog/https://blog.shadypixel.com/log-iptables-messages-to-a-separate-file-with-rsyslog/
https://gist.github.com/netson/c45b2dc4e835761fbccchttps://gist.github.com/netson/c45b2dc4e835761fbccc
https://www.rsyslog.com/doc/v8-stable/configuration/actions.htmlhttps://www.rsyslog.com/doc/v8-stable/configuration/actions.html
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#steps-32
step 4 of installing psadhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#psad_step4
"to omit syncing the file after every logging"https://www.rsyslog.com/doc/v8-stable/configuration/actions.html#regular-file
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
For the lazyhttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#editing-configuration-files---for-the-lazy
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#left-over
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#contacting-me
new issuehttps://github.com/imthenachoman/How-To-Secure-A-Linux-Server/issues/new
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#helpful-links
https://github.com/pratiktri/server_init_hardenhttps://github.com/pratiktri/server_init_harden
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
https://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#acknowledgments
https://www.reddit.com/r/linuxquestions/comments/aopzl7/new_guide_created_by_me_how_to_secure_a_linux/https://www.reddit.com/r/linuxquestions/comments/aopzl7/new_guide_created_by_me_how_to_secure_a_linux/
https://www.reddit.com/r/selfhosted/comments/aoxd4l/new_guide_created_by_me_how_to_secure_a_linux/https://www.reddit.com/r/selfhosted/comments/aoxd4l/new_guide_created_by_me_how_to_secure_a_linux/
https://news.ycombinator.com/item?id=19177435#19178618https://news.ycombinator.com/item?id=19177435#19178618
https://www.reddit.com/r/linuxadmin/comments/arx7xo/howtosecurealinuxserver_an_evolving_howto_guide/https://www.reddit.com/r/linuxadmin/comments/arx7xo/howtosecurealinuxserver_an_evolving_howto_guide/
https://www.reddit.com/r/linux/comments/arx7st/howtosecurealinuxserver_an_evolving_howto_guide/https://www.reddit.com/r/linux/comments/arx7st/howtosecurealinuxserver_an_evolving_howto_guide/
https://github.com/moltenbit/How-To-Secure-A-Linux-Server-With-Ansiblehttps://github.com/moltenbit/How-To-Secure-A-Linux-Server-With-Ansible
Table of Contentshttps://patch-diff.githubusercontent.com/objects/How-To-Secure-A-Linux-Server#table-of-contents
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http://creativecommons.org/licenses/by-sa/4.0/
How To Secure A Linux Serverhttps://github.com/imthenachoman/How-To-Secure-A-Linux-Server
Anchal Nigamhttps://github.com/imthenachoman
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