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OCS trying to connect to external SIP domains RRS feed

  • Question

  • Hello,

    Weve noticed that OCS 2007 R2 is trying to connect to some external domains like the following but get's blocked by the proxy server's:

    sip.example.com

    sipexternal.example.com

    sipinternal.example.com

    sip.firstname.lastname

    sip.(external company name) - I suspect this maybe consultants trying to login to their own company IM solution

    Automatic login works fine.  It would be useful to know why this is happening and if there is a way to stop it.

    Thanks.

    W.

    Friday, October 14, 2011 2:41 PM

Answers

  • When you install the Communicator client and run it as the very first time, the textbox where you enter your SIP address is someone@example.com

    If by mistake, any user clieck the sign in button without entering his/her SIP address, then the communicator tries to find the edge server for example.com for someone@example.com SIP address.

     

    I guess this is the reason why you are seeing these requests on your firewall :)

    hth

    Turgay

     

    Friday, October 14, 2011 11:08 PM
  • Hi,

    where do you see this messages? the only possible scenario that can happen is that the users specify wrong Domain names to loging to LYNC Client.

    When the Automatic login is enabled, it only check the presise external domain name (@domain) against the SRV record _sip._tcp.domain.com and it will find the domain and sign in.

    Thamara.

    Saturday, October 15, 2011 12:59 PM
  • Hi,Worb68_OCS,

    When the client is set to use automatic configuration, it uses the SIP URI that is provided by the user to discover which server it should sign in to. Communicator does this by using DNS SRV records published for the domain part of the SIP URI.

    For example, if the user enters a URI of sip:user@example.com, Communicator uses example.com to discover a SIP server that uses DNS. Communicator looks for the following SRV records in its search for an appropriate server:

    • _sipinternaltls._tcp.example.com
    • _sipinternal._tcp.example.com
    • _sip._tls.example.com

    If these records do not exist, Communicator queries for host (A) records:

    • sipinternal.example.com
    • sipexternal.example.com

    You can check the following document for the details about OCS client automatic configuration and DNS discovery process.

    http://technet.microsoft.com/en-us/library/dd637152(office.13).aspx 

    Regards,

    Sharon

    Monday, October 17, 2011 8:13 AM
    Moderator

All replies

  • When you install the Communicator client and run it as the very first time, the textbox where you enter your SIP address is someone@example.com

    If by mistake, any user clieck the sign in button without entering his/her SIP address, then the communicator tries to find the edge server for example.com for someone@example.com SIP address.

     

    I guess this is the reason why you are seeing these requests on your firewall :)

    hth

    Turgay

     

    Friday, October 14, 2011 11:08 PM
  • Hi,

    where do you see this messages? the only possible scenario that can happen is that the users specify wrong Domain names to loging to LYNC Client.

    When the Automatic login is enabled, it only check the presise external domain name (@domain) against the SRV record _sip._tcp.domain.com and it will find the domain and sign in.

    Thamara.

    Saturday, October 15, 2011 12:59 PM
  • Hi,Worb68_OCS,

    When the client is set to use automatic configuration, it uses the SIP URI that is provided by the user to discover which server it should sign in to. Communicator does this by using DNS SRV records published for the domain part of the SIP URI.

    For example, if the user enters a URI of sip:user@example.com, Communicator uses example.com to discover a SIP server that uses DNS. Communicator looks for the following SRV records in its search for an appropriate server:

    • _sipinternaltls._tcp.example.com
    • _sipinternal._tcp.example.com
    • _sip._tls.example.com

    If these records do not exist, Communicator queries for host (A) records:

    • sipinternal.example.com
    • sipexternal.example.com

    You can check the following document for the details about OCS client automatic configuration and DNS discovery process.

    http://technet.microsoft.com/en-us/library/dd637152(office.13).aspx 

    Regards,

    Sharon

    Monday, October 17, 2011 8:13 AM
    Moderator