Harden your OpenSSH confg , step by step instructions to making your ssh more hard to bruteforce and exploit.

Tested on: Centos 5 32Bit

! I recommend you install webmin before doing changes here !
Reason you say? if sshd dies, or firewall ****s up, you can fix it though webmin command line, and file editor.

Step 1: Backup your sshd config

cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak

Step 2: Add a regular user, if you not already got one etc..

adduser admin
passwd admin

Step 3: Edit running sshd_config

!Remember to change the port in your firewall also!

cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak

Find #Port 22, Change it to a port of your choice :

Port 22

Find #ListenAddress 0.0.0.0, Change to :

ListenAddress YOUR-IP-HERE

Find #Protocol 2, 1 , Change to :

Protocol 2

Find #PermitRootLogin yes, Change to :

!Remember that when you set this to no, you will need a other user to get root!

PermitRootLogin no

Find #MaxAuthTries 6 , Change it to :

MaxAuthTries 2

Add this line to only give access to "admin" account, or the other regular user you have:

AllowUsers admin

Example Config :

Port 5988
Protocol 2
ListenAddress 1.2.3.4
PermitRootLogin no
Banner /etc/motd
Subsystem sftp /usr/libexec/sftp-server
AllowUsers admin
MaxAuthTries 2

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