Deploying Cisco Jabber (MRA) to a CUCM Cluster can sometimes have its pitfalls especially when the firewall is managed by a third party vendor. Although, the all to common error message “Cannot Communicate with Server” can be frustrating to troubleshoot, the devil lies in the details. This can also be very useful when needing to provide debugs reports to third party firewall vendors to investigate further on your behalf.

1st step is to view the jabber log file, this can sometimes be a long file to extract the key bits of information you’re after.. One idea is just to find the “cannot communicate’ error message. Then reverse engineer the log file.

2nd step is open a wireshark session and attempt a jabber connection. This provides key details about the connection process and is very useful to pass onto the thirdparty firewall vendor. Analysing the packets will give you insights into the login process from the DNS SRV query to attempting connections to CUCM and Presence servers.

In the below example, I had to troubleshoot the “Cannot Communicate with Server” error message. This turned out to be a inbound Firewall Port issue. The vendor did not open TCP 5222 from Public to the Expressway-E device. I had to send the vendore this packet capture for evidence to investigate further into the issue. I’ve also included the error messages in the Jabber log file to complete the picture. TCP Port 5222 is used for XMPP connection to the Presence Server.

Putting the packet capture and the jabber log together, gives you a full picture of where Jabber is exactly failing in the connection process.