I'm having problems with the way udhcpc handles a renewed dhcp lease on my wan interface. Every time the lease is renewed (but without the ip being changed), all existing nat:ed tcp connections seem to break! This is more than slightly frustrating, since all my irc and msn connections reconnect. But what's even more frustrating is that I just can't seem to find out why this is happening! I've been digging around the hotplug system but I don't really get where anything would involve the nat tables.
Anyone else have a suggestion on where to continue?
This actually seems to be a problem with dnsmasq rather than with udhcpc. Since the udhcpc script creates a new resolv.conf every time the lease is renewed, dnsmasq detects this and reloads. This is strangely enough causing my Windows client to renew it's lease and drop all tcp connections. I haven't seen this behaviour using any other dhcp-server.
A working solution and improvement to this was to create a static /etc/resolv.conf containing only 127.0.0.1 and add resolv-file=/tmp/resolv.conf to dnsmasq.conf.
I have also noticed that dnsmasq is unable to provide an address to a linux box of mine running gentoo with dhclient. Dhclient keeps complaining over udp checksum errors. If I switch to udhcpc on the gentoo box, everthing works out fine. There seems to be a problem with the OpenWRT dnsmasq binary in combination with my Asus WL-500gP hardware.
(Last edited by term on 13 Jul 2006, 11:49)