Integration CUCM with Fax server

[Ben Yosef]

Hi everyone,

I have CUCM 12.5 integrate with fax server via sip trunk.

When I'm trying to send fax through my mail it works just fine, but when I'm trying to receive a mail I'm getting an error.

The error is:

The CUCM send INVITE SDP(t38) to the fax server

The fax server return 488 Not Acceptable Here

Keeps happening until the CUCM send BYE message.

I'm attaching a capture of the flow from the side of the fax server.

Also the VGW is working on MGCP

 

CUCM IP - 172.17.16.107 (PUB-107, SUB-109)

Fax Server IP  - 172.16.0.97 

Can you please help me with this.

[Nithin Eluvathingal]

Instead of t.38 try g711 passthrough. What fax server are you using ?

[Ben Yosef]

Hi, we are using FaxCore

I took the output from my VGW if it helps:

VGW-BneiBrak#sh running-config | section voice service voip
voice service voip
allow-connections h323 to h323
allow-connections h323 to sip
allow-connections sip to h323
allow-connections sip to sip
no supplementary-service sip moved-temporarily
no supplementary-service sip refer
supplementary-service media-renegotiate
redirect ip2ip
signaling forward none
fax protocol pass-through g711ulaw
h323

mgcp call-agent 172.17.16.109 service-type mgcp version 0.1
mgcp dtmf-relay voip codec all mode out-of-band
mgcp package-capability rtp-package
mgcp package-capability sst-package
mgcp default-package fxr-package
mgcp fax t38 nsf 000000
mgcp bind control source-interface GigabitEthernet0/0/0
mgcp bind media source-interface GigabitEthernet0/0/0
mgcp behavior rsip-range tgcp-only
mgcp behavior comedia-role none
mgcp behavior comedia-check-media-src disable
mgcp behavior comedia-sdp-force disable
mgcp profile default
ccm-manager fallback-mgcp
ccm-manager mgcp

[Nithin Eluvathingal · Accepted solution]

remove "mgcp fax t38 nsf 000000" and try the below. Either alaw or Ulaw. 

mgcp modem passthrough voip codec g711alaw
no mg

mg

[Ben Yosef]

Ok I did change it, now I will try to check,

The SIP profile is regular? any special changes?

Thanks for your helping 

[Roger Kallberg]

Does your fax over IP server support t38 and if so have you configured/enabled it on the server?

[Roger Kallberg]

Have a look at this old post, it looks to be a perfect match for your issue. https://community.cisco.com/t5/ip-telephony-and-phones/sip-based-fax-server-deployment/td-p/1371186