Inbound calls dropped after 10 seconds

[inventica]

Good day everyone!

I’d like to share my experience with UC560 to see if somebody had similar problems. We’ve been using UC560 with 10 SIP trunks for 2.5 years. Previously UC560 WAN was plugged directly into our router and had a Public IP. Because of various reasons we had to put it behind a firewall, which is the latest version of pfSense.  We configured 1-to-1 NAT mapping and everything worked except that inbound calls are dropped exactly after 10 seconds. I can make outbound calls fine. Inbound calls work and both parties can hear each other but after 10 seconds the line is cut off.

Some might say it’s firewall issue – but I’m not too sure why the firewall would block the call after 10 seconds? It either blocks traffic or it doesn’t, same with NAT it either translates packets or it doesn’t. Why cutting the call after 10 seconds

Here is how everything is set up:

pfSense WAN IP: 81.x.x.244

pfSense LAN IP: 172.16.0.1

UC560 WAN IP: 172.16.0.2

UC560 LAN IP: 192.168.10.4

If I change WAN IP of UC560 to 81.x.x.244 and plug it into the router – incoming calls work fine.

I also tried not to use WAN interface of the phone system and router traffic from LAN 192.168.10.4, but same problem – 10 seconds and the call is disconnected!

I would appreciate any troubleshooting advice or pointing me in the right direction.

Thank you

[David Trad]

Hi Inventica,

Can you please get a SIP debug capture of this event happening?

The following command is dangerous and should only be run for a short period of time as it can crash the system from overloading it, but it will be very helpful in assisting with the diagnosis.

Step-1:

Turn monitoring on the terminal "term mon" if you are using a console cable it is on automatically

Step-2:

debug CCSIP all

The above is what will crash the system if you leave it on too long, do no more than say 2-3 calls, also make sure putty has at least 2000000 lines in the settings so that way you can copy all to clipboard and post it in a text file.

Once you have this captured in a text file, please upload that file up here so we can see it

Cheers,


David Trad.

[inventica]

Thank you David. I attach our debug info

[David Trad]

Hi Inventica,

You seem to be having a lot of "401 Unauthorized" and surrounding the extension number "150", can you advise what this is all about?

I may need a snapshot of your running configuration to narrow down on this.

Cheers,


David Trad.

[inventica]

Hello David

I'm not sure there is anything special about 150 - it's just a Cisco desktop phone.

I attach my latest config

thanks

[inventica]

It appears that the problem lies with the SIP header:

v=0

o=CiscoSystemsSIP-GW-UserAgent 3243 2224 IN IP4 172.16.0.2

s=SIP Call

c=IN IP4 172.16.0.2

t=0 0

m=audio 17828 RTP/AVP 0 101

c=IN IP4 172.16.0.2

a=rtpmap:0 PCMU/8000

a=rtpmap:101 telephone-event/8000

a=fmtp:101 0-16

a=direction:active

UC560 states that its WAN IP is 172.16.0.2, which is correct but it's non routable, so our SIP provider is unable to communicate with the phone system. Looks like it won't work with any NAT. Is there any way to supress that?