PROBLEM
SoftPhone does not function over a VPN when dealing with multiple NICs
CAUSE
The network adapter used for VPN is not used for communication over the network.
WORKAROUND
Manually disable all other network cards to force binding to the NIC that is used for the VPN
RESOLUTION
Apply hotfix from link below in which the MiAUDIO connector has been changed to iterate over all network cards until one is found that can communicate with the PBX.
This hotfix must be installed on your Enterprise Server and you must be running version 5.5 SP1
This hotfix has been included in all subsequent software versions. For our latest software and updates, please go to www.mitel.com .
If you have a business need for this hotfix and are unable to update to a supported software version, please contact Customer Support for assistance.