[ILUG] ipchains query...

[Vincent Cunniffe]

kevin lyda wrote:

> using ipchains how can i block off listening ports on ppp0?  i'm getting
> errors like the following, which is caused by blocking off some ephemeral
> ports on the ppp0 interface.  what i really want to do is stop local
> daemons from listening on those ports.  i can do that by configuring
> each daemon on that box, but by doing it via ipchains (or something else)
> there's less to check (and less to go wrong).
> 
> Nov  6 01:00:54 inle kernel: Packet log: input DENY ppp0 PROTO=6 216.239.35.101:80 194.125.171.22:2937 L=60 S=0x00 I=5844 F=0x4000 T=49 (#16) 
> Nov  6 01:00:56 inle kernel: Packet log: input DENY ppp0 PROTO=6 216.239.35.101:80 194.125.171.22:2936 L=60 S=0x00 I=45401 F=0x4000 T=49 (#16) 
> Nov  6 01:00:56 inle kernel: Packet log: input DENY ppp0 PROTO=6 216.239.35.101:80 194.125.171.22:2934 L=60 S=0x00 I=3135 F=0x4000 T=49 (#16) 


You can specify an interface when configuring the rules, so put in a
blanket deny rule for incoming traffic to the relevant ports and add
a '-i ppp0' to the line. The daemons can then bind to whatever they
want, but the firewall will eat the traffic before it gets to the
listening daemons.

Regards,

Vin