On 2012-08-28 18:08, Mark Wickens wrote: I'm not totally clear on your setup. You have two interfaces, eth0 and eth2. I think I got that. And the bridge program is using eth0 for it's bridge. But how does your ethernet looks like? Is both eth0 and eth2 connected to the same physical network? Is the router on that same segment as well? Both interfaces are on the same segment as the router. What sessions are you seeing on the router? On the router I see the following sessions: ------------------------------------------------------------------------------- Private IP :Port #Pseudo Port Peer IP :Port Ifno Status ------------------------------------------------------------------------------- 192.168.1.126 4711 4711 130.238.19.25 4711 3 0 192.168.1.127 4711 4711 130.238.19.25 4711 3 0 Where 192.168.1.126 is eth0 and 192.168.1.127 is eth2 And what did the routing table on the machine running the bridge look like, if you have two interfaces? No idea on this one. The bridge program does not try to do anything clever with the UDP packets, so they will be sent on any interface, based on your routing table. It might sound as if your router/NAT was pointing at the IP address of eth0, but the default entry of the routing table on your machine would be using eth2. But this is all wild guessing right now... OK, that probably explains it. I thought the bridge was tied to that particular interface. It's worth pointing out that what I'm doing it probably daft - the 2nd card was installed to use for a SIMH instance, so I should probably de-configure it from an OS point of view. The bridge uses the specified interface for it's bridging. That is, DECnet packets will only be sent and received from that interface. UDP does not have an interface that specifies which network interface to use. You normally do not have any control over this aspect for UDP packets. The UDP transport that the bridge use is just plain UDP. And the destinations are all the non-local destinations specified in the config file. Exactly which network interface traffic to those destinations exit on is something up to your UDP/IP implementation. (Just clarifying that detail a little more...) Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol