I cannot make a PSTN call inbound to or outbound from an external client (outside the edge server)


  • PSTN calls work fine for clients attached inside the private network.  When I attempt to make a call from or to an external client it will ring, but when it picks up, it disconnects with Network Error.  We had this problem originally, but it started working when we opened the correct ports on the firewall. I don't what has changed.  We have a standard front end server with a colocated media server.  Media bypass is enabled.  It is connected via a SIP trunk to a Cisco CUCME system, which in turn has a SIP trunk to the carrier.  The Edge server has a consolidated edge (Access, Webconf and AV all share an IP address).  The edge server has two interface, one to the private and one to the DMZ.  NAT is enabled on the firewall (static one to one).  In the log, it shows

    Trace-Correlation-Id: 3526735724
    Instance-Id: 0001F284
    Direction: incoming;source="internal edge";destination="external edge"
    Peer: VSLync2010.domain.local:5061
    Message-Type: request
    Start-Line: BYE sip:;transport=tls;ms-opaque=6832440d7f;ms-received-cid=105700;grid SIP/2.0
    From: <sip:9167731743;;user=phone>;epid=4A60B12933;tag=3ca2df8cc
    To: <sip:301;;user=phone>;epid=bccfdda386;tag=91fa427ef5
    CSeq: 4389 BYE
    Call-ID: e4c83a81-8711-4aee-b322-bcc8fdf7ffe7
    Via: SIP/2.0/TLS;branch=z9hG4bKA8FDB4D5.F7930CE29642915B;branched=FALSE
    Authentication-Info: TLS-DSK qop="auth", opaque="25881EB6", srand="640C0615", snum="310", rspauth="dbd75d359ad8074f52cb4325576703c75277bf44", targetname="VSLYNC2010.domain.local", realm="SIP Communications Service", version=4
    Max-Forwards: 69
    Via: SIP/2.0/TLS;branch=z9hG4bK4ecffd76;ms-received-port=49587;ms-received-cid=2FE100
    CONTACT: <;gruu;opaque=srvr:MediationServer:iMHCjlxNrFqBYQ4hDwJ1ZQAA;grid=7a8332207bf4447683af4de14a8db53f>;isGateway
    SUPPORTED: ms-dialog-route-set-update
    SUPPORTED: gruu-10
    USER-AGENT: RTCC/ MediationServer
    P-ASSERTED-IDENTITY: "Mickey Mouse"<sip:9167731743;;user=phone>
    ms-diagnostics: 23;source="VSLYNC2010.domain.local";reason="Call failed to establish due to a media connectivity failure when one endpoint is internal and the other is remote";component="MediationServer";Exception="Proxy side ICE connectivity check failed.";ICEWarningFlags="ICEWarn=0x80120,LocalSite=,RemoteSite=,RemoteMR=,PortRange=49152:57500,RemoteMRTCPPort=53852,LocalLocation=2,RemoteLocation=0,FederationType=0"
    ms-diagnostics-public: 23;reason="Call failed to establish due to a media connectivity failure when one endpoint is internal and the other is remote";component="MediationServer";Exception="Proxy side ICE connectivity check failed."
    ms-endpoint-location-data: NetworkScope;ms-media-location-type=intranet
    Route: <sip:VSLyncEdge.domain.local:61273;transport=tls;maddr=;opaque=state:Ee.ae42wNeaNtcwnS09oaHl5nJgAA;lr;ms-received-cid=2B0C00>
    Message-Body: –

    Thank You,


    Tuesday, March 15, 2011 2:50 AM

All replies

  • "MediationServer";Exception="Proxy side ICE connectivity check failed."

    This indicated missconfiguration of your Edge. There are many posts here with similar issues.


    Tuesday, March 15, 2011 3:01 PM
  • Hi Drago, Thanks for the reply. I have read most of those other posts and checked my configuration and it seems right. Remember, I mentioned that it was working? It occured to me that I did my test (after we fixed the firewall issue) with a netbook with a built in 3G wireless adapter. I just tested it with that netbook again today and it works (outside the edge server). So, it doesn't work with a computer from home, through a NAT'd broadband connection, but it does work with a Verizon 3G wireless connection. I also had another one of my employees test it from home and it had the same (not working) symptoms for him (it will ring, but disconnects on answer). PC to PC calls (Lync Calls) work in either case. Also, the netbook is a member of the domain (I'm not sure why that would make a difference, though). John
    Tuesday, March 15, 2011 9:23 PM
  • Strange case, indeed.

    Carriers use Public IP addressing, so your conclusion “…it doesn't work with a computer from home, through a NAT'd broadband connection… is correct.

    Still… see this post: especially Alexandru comment from February, 21st .

    Might worth popping quickly a virtualized stand-alone mediation and test. If this resolves the issue, we must need to raise attention for this scenario to the PG group.




    P.S. Is it only me or someone else also have problem with Expolrer 9 RC and this forum?
    Tuesday, March 15, 2011 9:56 PM
  • Ok, I am going to test some different itterations first (netbook from my house through broadband - known good client and another employee from his house).



    Wednesday, March 16, 2011 12:20 AM
  • I have tested it from the netbook at my house and it fails.  If I switch the netbook to mobile broadband it works.  I had another one of my engineers (on a different ISP) test it from his house and it worked for him (he is NATing through an AT&T connection).  It appears to be a problem isolated to my home network.  The symtoms are the same as when we didn't have the range of ports open (TCP 50,000 to 59,999 and UDP 50,000 to 59,999).  At this point it is either my home router (Linksys) or my ISP (Surewest).


    Wednesday, March 16, 2011 4:05 AM
  • HEllo JJCal2006,

    It appears you are on the right track here. I have seen where some routers could cause this.  You could take your netbook and put it in front of the router to see if it is your ISP or the router. Big hopes on it being the router though. Geting an ISP to change port usages will be difficult to say the least. Usually out the box home routers do not have a problem with the ports used for the audio/video stream.  YOu make any changes to the router from the default config?

    Richard McGiboney, Support Escalation Engineer, Microsoft
    Friday, March 18, 2011 8:38 PM
  • Hello,

    Any luck with getting this issue resolved?



    Thursday, February 23, 2012 9:36 PM