Category Archives: SRV Record

No Presence for Fedrated partners – Event ID 11

08 Wednesday Jun 2016

Posted by in Error Codes, Event ID, Federation Issue, Lync DNS Records overview, Lync Edge, O365, Office 365, SRV, SRV Record, Uncategorized, Unified Messaging, voicemail

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Problem

Came across a deployment with the following 2 issues:-

  1. federated partners were showing up as presence unknown
  2. unable to call voicemail (hosted in O365)

When trying to send messages to these “unknown” federated partners I got “This message wasn’t sent due to company policy”.

So why did I try to message a contact with a presence status of “unknown? Simply because the federated contact could see my users presence and send me IM’s, I was even able to respond to these IM’s although the presence was still “unknown”.

Presence Unknown

Troubleshooting

A quick look at the client side logs revealed an error in the presence Subscribe message

CSeq: 1 SUBSCRIBE
Via: SIP/2.0/TLS 172.11.12.13:24164;ms-received-port=24164;ms-received-cid=FC9300
ms-diagnostics: 1008;reason=”Unable to resolve DNS SRV record“;domain=”ucsorted.com”;dns-srv-result=”NegativeResult”;dns-source=”InternalCache”;source=”access.ucsorted.com”
Server: RTC/6.0
Content-Length: 0

Taking a look at the users (client side) local event log I found the same error.

Event Log

Event ID 11
A SIP request made by Lync failed in an unexpected manner (status code 80ef01f8).

Response Data
504  Server time-out
ms-diagnostics:  1008;reason=”Unable to resolve DNS SRV record“;domain=”ucsorted.com”;dns-srv-result=”NegativeResult”;dns-source=”InternalCache”;source=”access.ucsorted.com”;OriginalPresenceState=”0″;CurrentPresenceState=”0″;MeInsideUser=”No”;ConversationInitiatedBy=”6″;SourceNetwork=”5″;RemotePartyCanDoIM=”Yes”

Clearly there is some issue with either the federation SRV record or resolving the federation SRV record.

Checking the SRV record from the Edge server I can see that this record is not found. Checking the DNS for the Edge server I noticed that the interfaces are pointing to the internal DNS servers.

Solution

We have 2 options here:-

  1. Configure the Edge Server to point to a public (external) DNS server where the SRV record for _sipfederationtls._tcp.domain.com is valid (frowned upon by some security folks)
  2. Add the SRV record for _sipfederationtls._tcp.domain.com to the internal DNS, making sure that the target FQDN is the Public Access FQDN of the Edge Server.

NOTE

Here is a little reason why you may want to avoid using the common sip.domain.com DNS name for your Edge Servers Access FQDN (only..). Internally the sip.domain.com record was generally configured to resolve to the front end pools, if we now need an internal SRV record for _sipfederationtls._tcp.domain.com then targeting this to sip.domain.com will simply get to the Front End Pool and not to the Federation point at the Access Edge FQDN.

 

 

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Lync SRV Records

21 Saturday Jan 2012

Posted by in DNS, Lync Edge, SRV, SRV Record

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I was configuring a new Edge environment today and thought I’d done it enough times not to have to refer to my notes. It was at this time that I realized that I hadn’t clearly documented the different SRV record options…only noticed as I had to take a peek 🙂

Internal DNS SRV
_sipinternaltls._tcp.  #for each sip domain (multiplied by each Front End Server)
If not using split brain DNS it is wise to add a sip. A record (I usually add it either way)

External DNS SRV
_sip._tls.    #for each sip domain
_sipfederationtls._tcp.  #for each sip domain

HOWEVER…
I did come across an environment that didn’t have the ability to add SRV records externally and were  not using split brain DNS.

External DNS add the following:-
       sipexternal. point it the the Edge Server Public FQDN (the consolidated name also works as long as its in the certificate as a SAN)

Internal DNS add the following:-
     sip. pointing to the Front End Server

More details on SRV records…

Lync Auto login SRV Record
Service: _sipinternaltls
Protocol: _tcp
Priority = 0
Weight = 0
Port Number: 5061
Host:

OCS Auto login SRV Record
Service: _autodiscover
Protocol: _tls
Priority = 0
Weight = 0
Port Number: 443
Host: sip.

Federation (Autodiscover)SRV Record
Service: _sipfederationtls
Protocol: _tcp
Priority = 0
Weight = 0
Port Number: 5061
Host:

PB

Lync Autodiscover SRV Records not possible

20 Tuesday Dec 2011

Posted by in autodiscover, DNS, SRV Record

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Sometimes you come across a situation when an SRV record cannot be created either externally on internally (for whatever reason)

Don’t despair as the clever folk at Microsoft development have implemented additional options should Lync Communicator fails to reach the Lync FrontEnd Server by means of the SRV record.

Discovery options are as follows:-
1. SRV
2. sipinternal.
3. sipexternal.
4. sip.

So by simply adding an A record as above and pointing it to the Edge Public interface (where the Access Edge role resides) you can get around using SRV. Do keep in mind that this will add a few seconds to the logon process.

Also keep in mind that some third party vendors have created product that uses SRV records to log in, of course these may need consideration.