Iptables prevents brute force ssh cracking

Based on the port, RainyFox uses iptables's connlimit module iptables-IINPUT-ptcp? Syn? Dport22-mconnlimit? Connlimit-above2-jREJECT a command can be done ,? Connlimit-above2 indicates that only one customer is allowed to open two sessions with sshd_config

RainyFox

Use the iptables connlimit module based on the port

Iptables-I INPUT-p tcp? Syn? Dport 22-m connlimit? Connlimit-above 2-j REJECT

A command can be used to commit ,? Connlimit-above 2 indicates that only one customer is allowed to start two sessions. In contrast to the setting of sshd_config, sshd_config can only set a maximum of several attempts by a user.

You can also set web service access limits.

Iptables-I INPUT-p tcp? Syn? Dport 80-m connlimit? Connlimit-above 30-j REJECT
In this way

Use putty to test and enable the third word to show that the network is unavailable, as shown in figure