A bit of Exchange help

nightmare99 · 12 May 2015 at 08:41

I'm helping a friend out with a small mail problem on an SBS 08 box so exchange 2007, generally everything works fine but domain users seem unable to email anybody @arun.gov.uk
They get message delayed NDRs then finally "550 4.4.7 Queue expired"

I suspect it may be relevant but an nslookup arun.gov.uk from the server does not resolve to anything.

Any ideas?

nightmare99 · 12 May 2015 at 09:49

Yeah its pointing to itself for DNS, in the forwarders there is the router's IP, the ISP's primary/secondary IPs & google's IP.

On the IP v6 network interface there is a static address set but the primary DNS is set to loopback

:1), I presume this is ok?

I think I will have to have a dig through the SMTP logs to see what is happening.

nightmare99 · 13 May 2015 at 07:28

Ok so it perhaps looks like a DNS problem I am getting this error in the smtp send log
"Domain of sender address [email protected] does not resolve"

Now the domain does actually resolve ok however if I run the find problems tool on mxtoolbox it does report "None of the name servers responded in a timely manner", is it possible the name servers are mis-configured or not working correctly?

nightmare99 · 14 May 2015 at 06:52

Yes the isp DNS & google DNS are in the forwarders. Looking at the logs Exchange connects to the recipient mail server and tries to send but the recipient mail server is unable to resolve the sending domain and closes the connection.

nightmare99 · 14 May 2015 at 10:43

I have checked rdns with mxtoolbox and it passes fine.

If I run a ping -a myexchangeip it gives

Reply from myexchangeip: bytes=32 time=40ms TTL=59

I have run the BPA and it shows no real error or warnings.

I suspect this is the issue below although if I do an nslookup it resolves ok, is it possible the name servers are just not responding quickly enough for the recipients mail server to resolve the DNS of the sending domain?

nightmare99 · 14 May 2015 at 10:55

PTR tool result

nightmare99 · 14 May 2015 at 11:16

Yeah its on a static and a rDNS / PTR was setup by the ISP some time ago, perhaps something has changed then as its not correct now. Can't believe I missed that, will contact the ISP and get them to correct it.

EDIT: How strange the issue seems to have corrected itself now.

Cheers for the help.