Thursday, September 11, 2008

Quick Tip: Testing DNS SRV Records with NSLookup

Office Communicator relies on Service Location (SRV) records in DNS for auto-configuration.  Frequently you can't create the external DNS record yourself so you need to ask your ISP or DNS provider to do it for you.

So if the service provider is swearing black and blue that the records have been created correctly but your external client is not finding the server checking your DNS configuration is a great place to start.

There is a tool in the OCS Resource Kit called SRVLookup that will fetch and parse the SRV records for a given domain for your review.

However if you are out and about and don't have the resource kit handy there is a quick and dirty way to check SRV records using NSLookup.exe in interactive mode from the command line.  The screenshot below shows the sequence of commands needed to test for the _sip._tcp SRV record for the mycompany.com domain.  Click for a bigger view....

nslookup

2 comments:

SBSorized Dale said...

wow - thanks so much for this helpful information!

I'm getting the 'I swear we did it' from the records host and I need to verify that what they did is right or wrong. The mobile phone isn't gaining the benefit of the SRV's supposed publicly published existence for some reason.

Big Latin said...

Thanks for this man, I'm using this for our Exchange 2007 issue with Offline Address books!