On 02/15/2013 08:53 PM, Johnny Billquist wrote: I was watching the MOP Console system ID messages from DECnet/E on simh, with an emulated LQA. Noticed something odd: the source address was broadcast. That's not valid, of course. The question is why that happened. The answer is that the emulation uses the address in slot 0 of the address filter as the source address. The hardware doesn't care what order the addresses go in as far as filtering is concerned; DECnet/E puts broadcast in slot 0 and the physical address in slot 1, followed by any multicast addresses. Is the SIMH behavior also what a real LQA does? That would be an interesting DECnet/E bug if so... Or does a real LQA just use the physical address, as a UNA would? Hi, Paul. Sorry for not responding sooner. Busy, as usual. However, I did mark this for some later investigation. However, I now realize that it's not trivial for me to test, as it would appear a RSTS/E system would help. :-) I honestly don't know how a real LQA do. Maybe John Wilson knows more, since he have been digging into these kind of questions way more than most people I know... Or else if you have some realistic suggestion on how I would test this on my machine, as I do have a 11/93 with a real LQA here (although an LQA plus). I can provide access to my RSTS/E machine with a DELQA if that would be helpful. -Dave -- Dave McGuire, AK4HZ New Kensington, PA