Re: Very strange DNS Problem; MX not found

2017-05-08 Thread Georg Sotsas
Hello and thanks for your answers, allowing TCP queries to our internal resolver fixed the problem. Kind regards 2017-05-05 22:41 GMT+02:00 Jörg Backschues : > On 05.05.2017 at 14:48h Georg Sotsas wrote: > > The mails sent to .x...@guilford.com >> remain in t

Re: Very strange DNS Problem; MX not found

2017-05-05 Thread Jörg Backschues
On 05.05.2017 at 14:48h Georg Sotsas wrote: The mails sent to .x...@guilford.com remain in the queue with this error: Host or domain name not found. Name service error for name=guilford.com type=MX: Host not found, try again Just workin

Re: Very strange DNS Problem; MX not found

2017-05-05 Thread Wietse Venema
Viktor Dukhovni: > > > On May 5, 2017, at 11:31 AM, Wietse Venema wrote: > > > > I would not exclude the possibility that the OP is using a greedy > > resolver that tries to look up A records when asked for MX, and > > then reports an MX lookup problem when it was actually the A query > > that f

Re: Very strange DNS Problem; MX not found

2017-05-05 Thread Viktor Dukhovni
> On May 5, 2017, at 11:31 AM, Wietse Venema wrote: > > I would not exclude the possibility that the OP is using a greedy > resolver that tries to look up A records when asked for MX, and > then reports an MX lookup problem when it was actually the A query > that failed because of the large resp

Re: Very strange DNS Problem; MX not found

2017-05-05 Thread Wietse Venema
Viktor Dukhovni: > > > On May 5, 2017, at 8:48 AM, Georg Sotsas wrote: > > > > The mails sent to .x...@guilford.com remain in the queue with this > > error: > > Host or domain name not found. Name service error for name=guilford.com > > type=MX: Host not found, try again > > This sounds

Re: Very strange DNS Problem; MX not found

2017-05-05 Thread Viktor Dukhovni
> On May 5, 2017, at 8:48 AM, Georg Sotsas wrote: > > The mails sent to .x...@guilford.com remain in the queue with this error: > Host or domain name not found. Name service error for name=guilford.com > type=MX: Host not found, try again This sounds like an error with *outbound* mail, pl

Re: Very strange DNS Problem; MX not found

2017-05-05 Thread Wietse Venema
Georg Sotsas: > Hello, > we are encountering a very strange problem on our Postfix (2.11.0-1ubuntu1) > Mail Relay. > > The mails sent to .x...@guilford.com remain in the queue with this > error: > Host or domain name not found. Name service error for name=guilford.com > type=MX: Host not found