How do I permanently block a remote IP address?

I have been using a network traffic monitor to look at some suspicious network activity and I found an IP from an entry.
I ran a WHOIS on the IP address and it shows a system administrator from Mumbai, India: 1.187.0.0

I live in the USA and I don't use any softwares, services, or programs from India.
I don't know anybody in India, and I don't go to Indian websites.
Therefore, I am OK with doing an IP block of the entire country of India if somebody knows how.

But my main question is how do I block any IP address in My Linux OS ?

I really would like to do this because the number of processes logging in from the remote address is kind of high.
It seems to start whenever I run it.

I tried running GUFW, but it's too complicated for me. I don't understand the syntax of IPtables.
So should i make changes in the command line itself or either use any Content filter tools ?

Learn iptables or install something like webmin which will give you a basic GUI access to iptables.

Dealing with the complexity of GUFW would be your most productive use of time, if your system has UFW on top of iptables. Otherwise you could work with the text interface for UFW, if your system has it.

Which distro are you on?

UFW is a front end for iptables. GUFW is a gui for UFW. You can certainly use those and they are simpler than iptables itself. However, I personally think you would be better served by dealing with iptables itself. It is a little confusing at first, but the time spent learning the basics is well worth it. Since we don't know your setup, if you are on a lan, wireless or what, no one can tell you exactly what to do. Look at the man page for iptables. You will probably want to put a drop instruction in the INPUT chain. You may also want to change the default policies to DROP for INPUT and ACCEPT for OUTPUT. The man page will tell you how to do all those things.

I find the iptables documentation pretty obscure, but these pages may help
http://www.cyberciti.biz/faq/how-do-...-linux-server/
http://www.cyberciti.biz/tips/how-do...ll-routes.html

I wouldn't block everything from India: you don't know where the things you use may be hosted, or the route over which data may travel.

I have everything from India blocked and have no problem. That doesn't mean someone else wouldn't, of course.

Might peek at Firewall Builder as it can create a pretty good table with minimal stress.

http://www.fwbuilder.org/

Might consider downloading, or building a white list too.