SSH Security Protection notes

 

1

 

Use IPTABLES

 

The command is as follows: iptables-a input-p tcp-s 192.168.1.1-j ACCEPT allows access to 192.168.1.1 (domain name can also be used)

 

Iptables-a input-p tcp -- dport 22-j DROP

 

2

 

 

 

Use the files under/etc/hosts. *

 

/Etc/hosts. allow and/etc/hosts. deny files

 

Add a rule in/etc/hosts. allow.

 

 

 

Vim hosts. allow

 

#

 

Sshd: 192.168.1.1

 

#

 

Vim hosts. deny

 

#

 

Sshd: all

 

#

 

 

 

The above means that only 192.168.1.1 is allowed

 

 

 

Iptables-a input-p tcp-m tcp -- dport 22-m state -- state NEW-m recent -- update -- seconds 60 -- hitcount 2 -- name SSH -- rsource-j DROP

 

Iptables-a input-P tcp-m tcp -- dport 22-m state -- state NEW-m recent -- set -- name SSH -- rsource-j ACCEPT

 

 

 

The above means that after two wrong SSH passwords are entered, SSH will not be accessible within 60 seconds and an SSH file will be generated in the/proc/net/ipt_recent/directory. record your IP address. of course, the time can be changed.

 

 

 

 

From: linghunhack Space