iptables-question

Hi! I have question about iptables: If I want to block e.g. telnet for my two ippp-devices I do it this way (this works very good :)): iptables -A INPUT -i ippp0 -p tcp --dport 23 -j DROP iptables -A INPUT -i ippp1 -p tcp --dport 23 -j DROP So my question: Is there a way that I don't need to write a rule for every single interface? Something like "iptables -A INPUT -i ippp0,ippp1 -p tcp --dport 23 -j DROP" (I know this does not work) At the moment I use 4 interfaces and I don't like to type all my rules 4 times and of course it's not nice to have such a big firewall-skript... Greedings <da_bug@gmx.net>