Service records and ports, VCS Express

Here are the service records needed to use the Tandberg VCS:      srv     1 0 1719      srv     1 0 1720              srv     0 0 5060               srv     0 0 5060                 srv     0 0 5061               srv     0 0 5061             srv     0 0 5061

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

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)

8 thoughts on “Service records and ports, VCS Express

  1. Can SRV Records be used for subdomains?

    i.e., srv 0 0 5060


    1. Hi!

      Yes they can.

      The domain in the SRV record needs to correspond to the domain used in the SIP/H323 URI though, so if your endpoint has address your example can be used.

      I use this a lot when integrating with other systems, eg. MS Lync. The Lync SIP domain is normally, while the Cisco/Tandberg domain would be to ease the routing between the to systems.

  2. Is it best practise to use different SIP domains when integrating Tandberg VCS with Lync?

    We have a small installation with a VCS Control and a VCS Expressway and the VCS Control is also acting as Lync Gateway.

    Can you recommend any good resources about Tandberg and Lync integration – apart from the official deployment guide?


  3. It’s not only best practice, it’s more or less required. There are always problems in the installations i’ve seen when the same sipdomain is used.

    I’ve never used anything other guides than the official ones, so unfortunately I can’t recommend anything else other than the internet :/

  4. Hei Tom,

    to put it in different words, the single domain setup requires an additional (internal) domain
    for internal devices and mapping via findme/ocs relay. But it works fine 🙂

    What is the reason that you list: srv 0 0 5061 srv 0 0 5061

    Also srv 1 0 1720 srv 0 0 5060
    are not really “needed” and can be seen as optional.

    If you have a vcs-e its even worth thinking about disabling 5060udp completly
    as this is way fewer used for video conferening then for voip scans 🙂

    In addition I would recomed a weight and priority of 10, the A/AAAA record
    “should” not only be there it MUST (not even CNAME), as it is required for SRV (see RFC2782)

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