Establish SSH server access via only a specific IP address

Establish SSH server access via only a specific IP address

Introduction

The purpose of this article is to explain the procedure of manipulating Iptables in order to grant access to a particular server only through a specific IP address. To do this you need to append a rule into the Iptables chain. Follow the article to successfully achieve this.

Login

Step 1: Login to the server that needs to be accesed from a single IP.

# ssh root@xxx.xxx.xxx.xx

Check Iptables rules

Step 2: Check the iptables rules by using the following command

# sudo iptables -S

Step 3: Identify the IP address of the primary server that you want to use to access the server with IP xxx.xxx.xxx.xx. Let this IP be yyy.yyy.yyy.yy.

Addition of new rule

Step 4:To add new rule use the command

# sudo vim /etc/sysconfig/iptables

Press the key I to enter edit mode.

Add the following rule to the Iptables rule of server with IP xxx.xxx.xxx.xx

-A INPUT -m tcp -p tcp -s yyy.yyy.yyy.yy --dport 22 -j ACCEPT

Purpose: This rule will allow access via port 22 only from the IP yyy.yyy.yyy.yy

Step 5: To save, press ESC key followed by :wq! and the hit the ENTER key.

Restart IP tables

Now, restart the Iptables for the changes made, to come into effect: 
/etc/init.d/iptables restart

Conclusion

Now the above added rule will only allow ssh access to the server with IP yyy.yyy.yyy.yy and block all other ssh input traffic.

[ht_message mstyle="danger" title="" " show_icon="" id="" class="" style="" ]Make sure to replace xxx.xxx.xxx.xx and yyy.yyy.yyy.yy with your corresponding IP Addresses.[/ht_message]

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