Hello,

I would like to setup my Linux server such that I only allow logins from certain machines (based on their IP). I was wondering if this is, first of all, possible at all. Further, if it is possible, could anyone point me towards how to do this? Any help is greatly appreciated.

Thanks,
RD.

Greetings!


To only allow specified IP adresses to access your server you have to first block all incoming connections:
iptables -P INPUT DROP

Then for example in order to allow a client using the IP 192.168.0.14 to access your FTP service, you will have to set up rules like the following:
iptables -A INPUT -i eth0 -p tcp -s 192.168.0.14 --dport 21 -j ACCEPT
iptables -A INPUT -i eth0 -p tcp -s 192.168.0.14 --dport 20 -j ACCEPT

This is assuming the client is in your local LAN and your according interface is eth0. To allow clients to connect via internet you need to change -i eth0 to your internet interface (eg ppp0) and of course the source IP.

I strongly suggest you the manual pages for iptables and the iptables HOWTO for more options!


Good luck!