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DNS problem - Cannot find SRV records RRS feed

  • Question

  •  

    Hello,

     

    I have a strange problem and hope that someone could help me with this.  I can connect to Server using Communicator when I am in the office.  I have problem when I am out of the office.

     

    I setup external SRV DNS records:

    _sipfederationtls._tcp..mydomain.com and

    _sip._tls.mydomain.com

     

    As I said, when I am out of the office, I cannot connect.  I decided to check ipconfig /displaydns and it tells me that I did not setup all of those records.

     

    After that, I run nslookup and this is the output that I have:

    Default Server:  resolver.qwest.net
    Address:  205.171.3.65:53

    > _sip._tls.mydomain.com
    Server:  resolver.qwest.net
    Address:  205.171.3.65:53

    *** resolver.qwest.net can't find _sip._tls.mydomain.com: Non-existent domain
    > _sipfederationtls._tcp.mydomain.com
    Server:  resolver.qwest.net
    Address:  205.171.3.65:53

    *** resolver.qwest.net can't find _spfederationtls._tcp.mydomain.com: Non-existent domain
    >

     

    I am not sure why is it trying to resolve it on the qwest.net.  I am connected to qwest now but the records setup somewhere else.

     

    Any ideas?

    Friday, October 12, 2007 12:13 AM

All replies

  • Hi

     

    To query for the SRV records, you should set the query type to SRV:

     

    Code Block

    C:\>nslookup -q=SRV _sipfederationtls._tcp.mydomain.com
    Server:  My_DNS_Server
    Address:  xxx.xxx.xxx.xxx:53

    _sipfederationtls._tcp.mydomain.com  SRV service location:
              priority       = 0
              weight         = 0
              port           = 5061
              svr hostname   = OCS1.mydomain.com
    OCS1.mydomain.com      internet address = xxx.xxx.xxx.xxx

     

    C:\>nslookup -q=SRV _sip._tls.mydomain.com
    Server:  My_DNS_Server
    Address:  xxx.xxx.xxx.xxx:53

    _sip._tls.mydomain.com       SRV service location:
              priority       = 0
              weight         = 0
              port           = 443
              svr hostname   = OCS1.mydomain.com
    OCS1.mydomain.com      internet address = xxx.xxx.xxx.xxx

     

     

    And you should have an A record for OCS1.mydomain.com or whatever is in you case.

     

    Lubo.

    Friday, October 12, 2007 5:58 AM
  • Thank you for your reply.  You were right, I forgot about that switch.

     

    Anyway, this is what I have now:

     

    Code Block

    C:\>nslookup -q=SRV _sipfederationtls._tcp.mydomain.com
    Server:  UnKnown
    Address:  192.168.1.1:53

    DNS request timed out.
        timeout was 2 seconds.
    DNS request timed out.
        timeout was 2 seconds.
    *** Request to UnKnown timed-out

    C:\>nslookup -q=SRV _sip._tls.mydomain.com
    Server:  UnKnown
    Address:  192.168.1.1:53

    *** UnKnown can't find _sip._tls.mydomain.com: Non-existent domain

     

     

    I tried it a few times and sometimes but the output is the same.  Sometimes it can switch like this:

    Code Block

    C:\>nslookup -q=SRV _sipfederationtls._tcp.mydomain.com
    Server:  UnKnown
    Address:  192.168.1.1:53

    *** UnKnown can't find _sipfederationtls._tcp.mydomain.com: Non-existent domain

    C:\>nslookup -q=SRV _sip._tls.mydomain.com
    Server:  UnKnown
    Address:  192.168.1.1:53

    DNS request timed out.
        timeout was 2 seconds.
    *** Request to UnKnown timed-out

     

     

     

    But it is the same.

     

    Any ideas?

     

    Thank you.

    Friday, October 12, 2007 4:24 PM
  • Hi,

     

    192.168.1.1 is not a publicly routable IP address. So is 192.168.1.1 your external DNS server?

    Based on your post, it seems like a DNS missconfiguration or wrong DNS server. You can try the following and post back the results:

     

    Code Block

    C:\>nslookup

    Default Server:  server.domain.com
    Address:  xxx.xxx.xxx.xxx

     

    > server Your_External_DNS_Server.YourDomain.com
    Default Server:  Your_External_DNS_Server.YourDomain.com
    Address:  xxx.xxx.xxx.xxx

     

    >set type=SRV

     

    >_sipfederationtls._tcp.mydomain.com

    >_sip._tls.mydomain.com

     

     

     

     

    Lubo.

    Friday, October 12, 2007 4:45 PM
  • Thank you for your reply.  I know that this is not routable IP but this is what it tells me.  I am trying it from one of my client's office and I do not know what is the real DNS server is there.  But I can go on the Internet, so it works.

     

    I tried it from 2 different office with different setup but I have the same result.  I think that it should work like it is without me specifying the DNS server, shouldn't it?

     

    Please let me know.

     

    Thank you.

    Friday, October 12, 2007 5:19 PM
  • As Lubo mentioned earlier you can confirm your SRV records resolution by following those steps, but if you are not aware of your External DNS Server than you can select External DNS Server which is "4.2.2.2"

     

    Check your SRV lookups, if they works fine than you should be IN.

     

    Also BTW why do you need _sipfederationtls._tcp.mydomain.com, this record is used when you do Enhance Federation with other domains.

     

    In Remote access we just need

     

    1.        _sip._tls.domain - for externalTLS connections

    2.        _sip._tcp.domain - for externalTCP connections

     

     

    Friday, October 12, 2007 7:24 PM
  •  

    Download the reskit and install.

     

    Run srvlookup.exe to verify that your SRV's are working.

     

    regards

     

    Adrian

    Monday, October 15, 2007 3:59 AM