ip_conntrack and interfaces with dynamic ip addresses (ppp)
Mon, 06 Aug 2001 08:20:40 -0400
Truxton Fulton wrote:
> I have a situation where I use a ppp connection to send udp packets
> from a specific port to a specific port at a specific destination.
>>From time to time my ppp connection drops and comes back up with a
> new ip address. The entry in /proc/net/ip_conntrack retains the
> ip address of the old ppp interface, so any udp packets sent with
> the same source port are sent using the old IP address. If I wait
> for the entry in /proc/net/ip_conntrack to expire (3 minutes),
> then I can send my udp packets using the new IP address. Is there
> a way to explicitly delete an entry in the connection tracking table,
> or to flush the whole thing? I can compile conntrack as a module
> and rmmod/insmod, but that seems inelegant. Is there a better way?
> I am using linux 2.4.7 and iptables v1.2.2
You can apply the ctnetlink patch in p-o-m, then write a program
which, in some fashion, detects interface changes and flushes the
conntrack table of all entries with the old IP. It's a more elegant
solution than using insmod/rmmod.