Issue with Redirecting Callers to Unity Connection Call Handlers

William Bell
Vice President, Solutions and Products

The Scenario

The scenario is pretty straightforward. We have Cisco Unified Communications Manager (CUCM) 8.5(1)SU3 and Cisco Unity Connection (CUC) 8.5(1)Su3. The use case is that we want to allow CUCM users to transfer callers to the voice mailbox of another Unity Connection subscriber.

The Normal Behavior

So, I have been working with Unity/Unity Connection for many years and this whole transfer a caller to another mailbox thing has been around almost as long. I recall reading a Cisco document on how to accomplish this back when deploying CallManager 3.1(4b). The procedure worked well then and has been a staple forever, well at least until I tested it with Unity Connection 8.5.

What is “Normal” anyway?

Hailey and I are building out this system, we are applying our standard build, and we go into validating configurations. It is at this time we realize that we can’t transfer callers to another user’s mailbox. Not only that, but we can’t get into CUGA or access any of the other Call Handlers we have on the system. Instead of going to the proper Call Handler or conversation, calls are getting opening greeting or the subscriber sign-in conversation. Which are both accessed via Direct call routing rules.

Since we use bogus lines on a bogus CTI Route Point to hit our call handlers, we know to look at redirection (aka forwarding) rules in Unity Connection. We check configurations and everything appears to be what one would expect.

We monitor calls coming into Unity Connection and at first glance everything appears normal. We go through another round of double checking and triple checking everything to no avail. This is such a simple thing, why can’t we find the issue?

We accept that our configuration is correct. So now we are in the wonderful world of “bug” hunting. Fortunately for us the Cisco Support Community (CSC) exists. With a few searches we come across a thread where some poor soul ran into the same issue.

What’s in a name?

The solution, as absurd as it sounds, was to remove any occurrences of the words “voice” or “mail” in the alerting or display name fields. When I first read the thread I was like “no way”. I re-read it twice just to see if someone later in the thread would contradict this naive suggestion and offer the “true” root cause. Instead I found 2 or 3 people who confirmed that this was indeed the fix.

With some skepticism I say “what the hell” and modify the alerting and display fields. As soon as we applied the configuration, everything worked as it should. We put the words “voice” and “mail” back in just to see, and sure enough it breaks.

I took another look later on in the build out using Port Status Monitor and you can see that in a failed call (you know, one where the alerting/description field has “voice” or “mail” configured) the RedirectingId is blank. This is the reason the forwarding rules are not engaged and the Attempt Sign-In conversation or Opening Greeting (depending on where you call from) is.

This one was so ridiculous that I just had to share. Now I wonder what happens if the phone line in the “mail room” is redirected to Unity Connection. I may have to test that out just to see how deep the rabbit hole goes. For now, I am done with this one.


A colleague recently forwarded the following URL to me about CCM 3.2.2 voice mail integration. At the bottom of the page there is a note about using “Voicemail” in the alerting or display name fields. Interesting given that I have use the term ‘Voice mail” in builds since CCM 4.1 and didn’t hit an issue until CUCM 8.5. Now, the question is: how curious am I?

Transferring Calls Directly to Voice Mail with Cisco CallManager 3.2.2 spD

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Nick Kelly

Cybersecurity Engineer, Cisco

Nick has over 20 years of experience in Security Operations and Security Sales. He is an avid student of cybersecurity and regularly engages with the Infosec community at events like BSides, RVASec, Derbycon and more. The son of an FBI forensics director, Nick holds a B.S. in Criminal Justice and is one of Cisco’s Fire Jumper Elite members. When he’s not working, he writes cyberpunk and punches aliens on his Playstation.


Virgilio “BONG” dela Cruz Jr.

CCDP, CCNA V, CCNP, Cisco IPS Express Security for AM/EE
Field Solutions Architect, Tech Data

Virgilio “Bong” has sixteen years of professional experience in IT industry from academe, technical and customer support, pre-sales, post sales, project management, training and enablement. He has worked in Cisco Technical Assistance Center (TAC) as a member of the WAN and LAN Switching team. Bong now works for Tech Data as the Field Solutions Architect with a focus on Cisco Security and holds a few Cisco certifications including Fire Jumper Elite.


John Cavanaugh

CCIE #1066, CCDE #20070002, CCAr
Chief Technology Officer, Practice Lead Security Services, NetCraftsmen

John is our CTO and the practice lead for a talented team of consultants focused on designing and delivering scalable and secure infrastructure solutions to customers across multiple industry verticals and technologies. Previously he has held several positions including Executive Director/Chief Architect for Global Network Services at JPMorgan Chase. In that capacity, he led a team managing network architecture and services.  Prior to his role at JPMorgan Chase, John was a Distinguished Engineer at Cisco working across a number of verticals including Higher Education, Finance, Retail, Government, and Health Care.

He is an expert in working with groups to identify business needs, and align technology strategies to enable business strategies, building in agility and scalability to allow for future changes. John is experienced in the architecture and design of highly available, secure, network infrastructure and data centers, and has worked on projects worldwide. He has worked in both the business and regulatory environments for the design and deployment of complex IT infrastructures.