I am trying to block many entire blocks of IPs with iptables, and with what information I can find, it would appear that I block IPs with:

iptables -I INPUT -s 25.55.55.55 -j DROP

If I wanted to block 25.25.25.25.

However, say I wanted to block 30.30.*.*, or 212.9.*.*. How would I do this?

iptables -I INPUT -s 30.30.0.0/255.255.0.0 -j DROP
iptables -I INPUT -s 212.9.0.0/255.255.0.0 -j DROP

good luck

Thanks for that reply, I'll give it a shot, could you tell me how that works though - so I could apply it to any range of addresses.

Logically to me it looks like 212.9.0.0/255.255.0.0 would block 212-255.9-255.0.0, if you see what I mean...


To block say 234.*.*.* would I use 234.0.0.0/255.0.0.0, and to block 123.212.232.* would I use 123.212.232.0/255.255.255.0?

Thanks very much.

yes u r right.

good luck

Well this stopped my spam problem I had been unknowingly adding ips to the /etc/rblblacklist
using exim4 and trying to stop the spam madness 0- however it seems according to exim you can only use example.com format in that blacklist - not ips
So I used your iptable method and it worked so well im just sittin here gloating im so happy thank you for the killer thread - Ive always just let iptables run automatically and never touched it manually but I was happy to do so today!
Now after doing some extensive reading about iptables I am concerned -
It took me a good deal of time to enter all these ips into it -
and according to what I read - if iptables is restarted or the unit reboots this data will be lost of all the ips I have entered - is this true? and How can I prevent my valuable list of blocked ips from disappearing during reboot?

Thanks!!!

AJD

u can save current iptables rules like that:
iptables-save > /etc/iptables.rules

after that u can load the rules that u saved, like that (u can add the following line in rc.local file. so iptables will load your rules for every restart):
iptables-restore < /etc/iptables.rules

btw: if u use redhat or fedora u can prefer following:
/etc/init.d/iptables save
and it will save the iptables current rules. if u enable service of iptables on boot, it will load your rules during the starting system.

good luck.