Mitel MiVoice

Mitel Troubleshooting: Call re-routing and forwarding being ignored

If you have a chain of call re-routing and forwards, but it does not progress beyond a certain extension regardless of the Day, Night1, and Night2 rules, it may be that Call Forward – End Chaining is enabled on the extension.

Call Forward – End Chaining is enabled via a dialled feature access code, usually in some format containing the digits 64.

Feature access codes are programmed individually on the Mitel system, so it is not easy to tell what the code would be without reviewing it in the system.

There isn’t a way to identify whether it is turned on, but there is a separate code to cancel the Call Forward – End Chaining, look up the feature access code Cancel Call Forward – End Chaining

Mitel MiVoice

Mitel MiVoice 3300 Graceful Failover

To fail over phones from their primary to resilient controller before a shut down, use this maintenance command


The hand-over status can be checked with the command


After a reboot of the controller that handed off the phones, the phones will eventually migrate back to the original controller in 5 minute intervals.

Mitel MiVoice VoIP

Mitel MiVoice Business: Understanding Class of Restriction

Class of restriction (COR) is an important feature on MiVoice controllers for protection and control over what calls can access an outgoing trunk group.

COR can be split into two parts, the class of restriction group themselves, and its members which are defined by an Class of Restriction number.

Confusion can occur since class of restriction group are also identified with a number, so it’s important to distinguish between a class of restriction group and a class of restriction number.

If a class of restriction number if part of a class of restriction group, the station associated with that number will not be able to access the outgoing route. To summarise, if a class of restriction is a member of a class of restriction group, it is blocked.

Classes of restriction can assigned to groups in the form System Properties > System Feature Settings > Class of Restriction Groups

Different parts of the system will utilise a class of restriction group to control its use, or can be assigned a class of restriction identifier to be used within groups.

Utilises a Class of Restriction Group

ARS Route (Blocks access to route)

ARS Leading Digits (Blocks access to a route as soon as leading digit is received)

Assigned a Class of Restriction Number

Station Attributes (COR assigned to individual phones)

Trunk Attributes (COR assigned to external trunks)

Use cases of class of restriction can include:

  • Stopping voicemail ports from dialing out of an external trunk
  • Only allowing international dialing for a select class of stations
  • Preventing an incoming trunk call from being able to dial out of another trunk
Mitel MiVoice VoIP

Capturing a SIP trace / PCAP on a Mitel Controller

Capturing a SIP trace can help in diagnosing issues with SIP communications on a Mitel controller.

Log into the System Administration Tool and and navigate to Maitenance and Diagnostics, Maintenance Commands.

In the command box, type SIP TCPDUMP ON

At this point, run any test calls that you need to capture into a PCAP file.

Once test calls have been completed, remember to to type SIP TCPDUMP OFF. If you don’t turn off the capture it will continue to fill up hard drive space on the Mitel controller.

Now open a FTP client and navigate to the IP address of the Mitel controller, use the same credentials you use to log into the web interface as the credentials to log in via FTP.

With the FTP connection established, navigate to the directory path /vmail – in this folder you will find the .pcap file containing a trace of all the calls made on the system during the capture window.

Happy troubleshooting!

Mitel MiVoice VoIP

Poor ISDN call quality – Mitel / MiVoice 3300

We were tasked to look into a MiVoice Business controller in the UK that had been recently rebuilt from backup. Incoming or outgoing calls to the controller turned any calls into almost inaudiable noise.

Checking the ISDN forms against best practice it looked like nothing had been missed or mis-set, it was restored from a backup after all.

The key factor was eventually realised that this Mitel controller was freshly rebuilt with software reinstalled – the country was not set correctly! It was set to North America rather than United Kingdom.

The country setting of North America had messed with the codec/tones of the ISDN, so was producing the horrible noise on the phone line.

The Mitel controller during an out of hours window was set to United Kingdom in the country settings, system reset, and back-up restored.

The Mitel controller was back online, a call tested, perfectly clear audio.