[OxLUG] DNS failure over powerline

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Author: Philip Allen
Date:  
To: oxlug
Subject: [OxLUG] DNS failure over powerline
I have a DNS server 10.0.0.2, and /etc/resolv.conf includes the line
"nameserver 10.0.0.2"

I have a wireless AP, MAIN, which works fine.

If I connect to Trendnet 410AP ethernet over powerline AP, APPENDAGE,
DNS fails. /etc/resolv.conf is unchanged. host -v returns:

Host www.bbc.co.uk not found: 2(SERVFAIL)
Received 31 bytes from 10.0.0.2#53 in 2335 ms

However, I can log in to 10.0.0.2 while connected to APPENDAGE, so it
doesn't look like a physical connectivity problem. And if I run host on
10.0.0.2 it succeeds.

I have browsed to APPENDAGE but, as a mere AP, it doesn't provide any
DNS config.

I have run journalctl -f on 10.0.0.2. When I request a servername that
doesn't exist, I get "NAMED... REFUSED", whether I'm connected via MAIN
or APPENDAGE. The implication is that APPENDAGE is eating responses on
port 53, which looks like a hardware or firmware failure. I can't think
of any reason why 10.0.0.2 would refuse requests.

Can anyone do better than that ?

Thanks

Philip

-- 
Philip Allen
9 Bardwell Road             
Oxford  OX2 6SU                         +44-1865-311711
United Kingdom