Video calls from internet using H323

[Fabio Alvarenga]

Video calls from internet using H323 do not work. When I call to (conference room)@domain.com.br do not work. But when I call to (conference room)@(Ip address) the communication works perfectly. What could be happening ?

[Jens Didriksen · Accepted solution]

This indicates that the site you are calling does not have DNS SRV records in place which points to the relevant device the system is registered to; i.e. a Gatekeeper, VCS, SBC etc.

/jens

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[Patrick McCarthy]

I agree with Jens - it's easy to check, here is the command (on Windows) to check for H.323 lookup services:

nslookup -querytype=srv _h323ls._udp.domain.xx

Try that replacing domain.xx with whatever you are using. If you try that with cisco.com you'll get a lot in your response, my guess is on your domain you'll get nothing. 

The other possibility is whatever you are calling from doesn't have DNS configured correctly so it has no way to query a DNS server to resolve the domain. It's one or the other (or both).