I am using Fedora 6 for my web server. I frequently use Putty to connect to my server via ssh from home. My server also receives thousands of failed attempts from others to connect per week. I guess I have a good password or something, but there is no need to allow this to continue.

So my question: Is there a way to drop all attempts on port 22 except those from my IP address range? All my home computers use DHCP, but always have an address beginning with 138.190.208.something. So I would like to only allow a corresponding range of IP addresses, and drop the rest. I do need to keep accepting all connections to port 80, of course.

This is what my iptables list looks like now:

Suggestions? Thanks.

You could try somthing along the lines of ;

iptables -A INPUT -p tcp --dport 22 -s ! 192.168.0.1/24 -j DROP

course you'll most likley have to change the subnet

or you could change

to

Thanks for the replies. Those are good ideas. I don't have a ton of experience yet, so ideas like that don't always come to me on my own.

What would be the notation for all IP addresses starting with 138.190.xxx.xxx? I live on a university campus, and I have found that the last two sets of numbers in my IP address are the only ones that vary for me under DHCP. I have seen notation such as xxx.xxx.xxx.xxx/24 used before to denote an IP range, but I don't know what it means.

That's called CIDR notation. Read this link to understand how it works. If you don't want to worry about making subnet calculations, you can specify the ranges you want the rule to apply to in this manner:The equivalent CIDR notation way for this range would be:

i think you need some form of IP Subnet Calculator for that.
see: http://www.subnet-calculator.com/

or google for it....