SIP trunk CUCM 11.5 > Ayava CS1K, and DNS Issue

[TrickTrick]

HI everyone,

I'm facing a real problem these days trying to make a SIP trunk work between CUCM 11.5 ( which I control) and Avaya Call manager ( Nortel CS1000 SIP GW release_7.0 version )

first, I can make calls from CUCM towards Avaya ,no issues. The problem occurs when they try to call me, nothing happens

Tried to move the SIP trunk from the call manager to the VG, same thing, and to troubleshoot, here's what I did :

-SSH to the VG > Terminal monitor + debug ccsip messages : I did this in both directions ( when calling and called), and noticed this in the VG :

WHEN I'M CALLING :

Received:

SIP/2.0 100 Trying

From: <sip:9999@X.X.X.9>;tag=5056D6B9-1C04           #9999 is my extension, X.X.X.9 VG IP @

To: <sip:8888@X.X.X.5>    #8888 destination extension, X.X.X.5 IP of Avaya CM

WHEN CALLED :

same as the above traces but the domain name instead of the IP addresses :

From: "Mike" <sip:8888@Mydomain.com;user=phone>;tag=758f028-53c1dac-13c4-55013-1059b8e-5b615dd6-1059b8e

To: <sip:9999@Mydomain.com;user=phone>

My though is that : I send IP addresses to the Avaya CM, and the call is made correctly, but when they send a domain name instead of the IP address, no DNS resolution is made and the call can't be done 

My call manager has "WARNING: DNS unreachable", I have the DNS ip address configured correrctly in CUCM, I can ping it, "Utils diagnose test" shows that the DNS still has a problem

What should I do ? They control the DNS, should I ask them to add entries ? which hostname should I give, My CUCM has only the IP address in the "hostname/IP address" field.

Thanks in advance for the Support 

[Dennis Mink]

you can ignore that DNS unreachable notification, its a false positive, it does a reverse lookup of some sort that fails. check the community for posts on it.

your sip problem, you would need to supply us with the full SIP trace of the failed cucm inbound call so we can see why it fails.

also, when you say it fails does the phone actually ring or is it just no audio when picked up?

[TrickTrick]

Hi Dennis,
So I should not have any entry of CUCM in the DNS ? I did a utils diagnose test here's the line about the DNS
"test - validate_network : Reverse DNS lookup failed"



Here's a SIP trace of an Inbound call https://pastebin.com/7y73qGUh, Added some commentaries after "#"

"when you say it fails does the phone actually ring or is it just no audio when picked up?"

it gives a fast busy tone

Another thing confuses me, is that in the other cisco branches no domain name is set, while i'm using a domain name, should I remove it ?