codesalot.com

I made a quick and dirty php script to check if your domain is correctly configured in DNS to support standards based URI dialling. Just input your URI domain and your target gateway, and the script will check if the SRV records are correctly configured and that the A record for the gateway exists.

I’ll add more functionality and nicer looks as time goes by feature requests in comments.

http://www.codesalot.com/dnscheck/

Doug Lawty has written an excellent blogpost about OCS and split brain DNS and how to configure it:

http://blogs.technet.com/dougl/archive/2009/06/12/communicator-automatic-configuration-and-split-brain-dns.aspx

Here are the service records needed to use the Tandberg VCS:

_h323ls._udp.company.com      srv     1 0 1719 vcs-e.company.com.
_h323cs._tcp.company.com      srv     1 0 1720 vcs-e.company.com.
_sip._udp.company.com              srv     0 0 5060 vcs-e.company.com.
_sip._tcp.company.com               srv     0 0 5060 vcs-e.company.com.
_sip._tls.company.com                 srv     0 0 5061 vcs-e.company.com.
_sips._tls.company.com               srv     0 0 5061 vcs-e.company.com.
_sips._tcp.company.com             srv     0 0 5061 vcs-e.company.com.

There should also be an a-record pointing to the vcs express. (in this example, vcs-e.company.com)

Also, should anyone ever need it, here are the ports that an endpoint needs opened outbound if it is registering directly to a VCS express:

TCP/2776 (Q931/H245 for external traversal endpoints)
UDP/2776 (RTP Media from external traversal endpoints)
UDP/2777 (RTCP Media control traffic from external traversal endpoints)
UDP/1719 (H323 RAS signaling from gatekeepers/VCSes and traversal endpoints)
TCP/1720 (Q931/H.225 call connect signaling)

UDP/5060 (SIP signaling)
TCP/5060 (SIP signaling)
TLS/5061 (Encrypted SIP signaling)

This guy has described the autologin mechanism in a great way. It basically relies on DNS records.

Chief Architect’s Corner: Microsoft Office Communicator Auto-discovery Mechanism