Exchange help needed

[sluggster66]

Our setup

 

Exchange 2010

Server 2008

 

This morning all external send and receive mail stopped working, internal is fine.

 

I don't really know where to start looking. We had a DNS server on this box which hadn't been working properly so this was removed. ( has worked for ages )

 

The server is pointing at our other 2 DNS servers and Nothing has changed with these.

 

Any pointers would be great.

[dhicks]

I don't really know where to start looking.

 

The Exchange Management Console on your Server 2008 machine would be the place to start - look at the Send Connectors for more details of how your email server expects to send email. This could be an external issue - what kind of Internet connection do you have? Do you send your emails to the outside world via a smart host, or directly? Have there been any firewall changes recently?

 

We had a DNS server on this box which hadn't been working properly so this was removed. ( has worked for ages )

 

Do you mean "we removed the DNS server ages ago, email carried on working just fine until now" or "we removed the DNS server yesterday, it was working for ages until then"?

[sluggster66]

Hi dhicks

 

We removed the DNS server this morning. It had not worked for a few weeks. Everything looks ok as far as DNS set

 

No firewall changes. Don't think the issue is external.

 

Thanks for taking the time to give some suggestions

[dhicks]

We removed the DNS server this morning. It had not worked for a few weeks. Everything looks ok as far as DNS set

 

If you removed DNS this morning and email promptly stopped working, it does rather suggest something's not right DNS-wise. Does the Server 2008 machine know it's not now using itself as a DNS server - have you done a "ipconfig /flushdns" just to be sure? What are your external MX records set to - any chance you were hosting your own external DNS server (not likly, but you never know)?

[jbunoomally]

We recently had an issue similar to this (intermittent external mail flow/queuing) - we ended up changing the network config of the send connector from using an FQDN to an IP and it's been fine since for the past month (touch wood).

 

JB.

[Domino]

It's also worth looking in server config > hub transport > right click server and properties

 

there's an 'external DNS lookups' tab that can be used to set the DNS lookups to use different servers than the servers configured adapters. The send connectors also have a check box marked "use source server's external dns lookup" to enable this.

[RobD]

The Mail flow Troubleshooter (in Toolbox) may be worth a try.

[sukh]

All working? Check protocol logging & exch rca.