You aren't blocking UDP 53 from them are you? -----Original Message----- From: Af [mailto:[email protected]] On Behalf Of Adam Moffett Sent: Thursday, April 09, 2015 1:26 PM To: [email protected] Subject: Re: [AFMUG] Weird network issue
We did try Google DNS. No response. That's why I wanted the ASA config. > So when they are on their backup they can ping anything by IP and it returns > properly. When they nslookup the return does not come back from their DNS > server or ANY whatsoever. Like you tried AT&T's and Googles? Can they ping > that DNS server and receive a return? > > Are they using any tunnels? I've seen customers with issues like this before > being multi homed and having VPN's that will only work on one connection. > > ----- Original Message ----- > From: "Adam Moffett" <[email protected]> > To: [email protected] > Sent: Thursday, April 9, 2015 7:06:02 AM > Subject: [AFMUG] Weird network issue > > I have a customer who uses us as a backup path to the internet. They > have BGP sessions with us and another provider, and we just stack a > few prepends on the routes they send us and re-advertise them. > > When their primary connection is out, they report having partial > connectivity. We just had a two hour test window where their primary > connection was shut off on purpose so that we could test. The other > provider and I spent a ton of time going over BGP and routing stuff > and finally concluded, "gee, it should be working." > > After we gave up looking for a routing problem that isn't there, we > did some more basic testing and really the only thing I can conclude > definitely doesn't work when they fail over to us is DNS. Using > nslookup they get no response from any DNS servers. > > They have a Cisco 2811 running BGP, but that connects to an ASA, and > everything on their LAN is behind the ASA. > > I asked for copies of the configs on the 2811 and the ASA, but I'm not > even sure what I'm looking for yet. Any brilliant ideas?
