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C-series SRV registration


Dear Forum!

I'm facing the following issue. One of the older C20's is configured to register to a gatekeeper using a specific domain, which is equipped with the appropriate srv records (h323rs, h323ls and h323cs). The C20 is running the version TC3.1.1. According to a tcpdump made on the device first it queries some A records of the given domain, and if none defined it queries the defined SRVs onvards.

Tha same C20, upgraded to TC5.1.4 first queries the SRV records, and if none found it looks further to the A records defined for the given domain.

The problem is if an A record is defined for the domain, the old version thinks that this A is the gatekeeper, altough it could be for example a web server of the domain or something else, and tries to register to it. But it will fail, because it is not a gatekeeper. And it won't go further to query the srv records.

Is there a way, without upgrading the endpoint to the newest, to force the system to ask for the SRV records first if it wants to register to a domain-specific gatekeeper?

Many thanks for the answer!


Balazs Molnar

2 Replies 2

Martin Koch

To have proper SRV support I would go with TC5, TC4 might also work, but there were also some bugs.

Anyhow I would strongly recommend to upgrade your endpoint to the TC5.1.5.

You do not need to register to a specific domain, you can also set a dedicated a record pointing to your registrar/gk,

maybe with a smaller TTL if you have a cluster, then in failure case you can at least change the DNS as

you will not have the srv features.

Please remember to rate helpful responses and identify

As Martin mention, several bug fixes added in TC5.0.0 release for SRV base H.323 Gatekeeper registration and failover.

I have tested most of registration and failover scenarios with EX90 running with TC5.0.0 and confirmed its behave as expected (where had several challenges while I tested with TC4.2 software).

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