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7940 having problems over a static VPN connection

We have a number of users with IP phones, connecting to our Call Manager via static hardware based VPNs.

All the phones are configured in exactly the same manner and nearly every one works as expected.

However, one user's phone is having a particular issue that even blowing away it's registration and rebuilding the phone within the Call Managers hasn't fixed.

If the user tries calling an internal extension directly (i.e. x1111), the display shows the call being connected but once the other end picks up, the VPN caller hears silence even though the display shows the call as connected.

The same thing happens if the VPN caller attempts to dial a local outside number (i.e. 9,555-1212).

However, if the VPN caller attempts calling that same internal extension by using it's FULL dial string (i.e. 9, 1-555-555-5555), the call routes out and then back in from the outside POTS network, connects and both ends hear each other fine.

This issue ONLY occurs with this one user's phone.

Every other VPN phone user's phone and connection is configured in exactly the same manner, and they all still work exactly as expected.

The Call Managers are on version 3.3.1(4a), if that actually matters, and all the phones are on the latest firmware rev. 5.0(3.0).

Very odd indeed.

Any ideas?


Re: 7940 having problems over a static VPN connection


Are the other workng phones on the same subnet as this problematic phone? If not then the first thing that comes to mind is a routing issue. Make sure a PC from the central site can ping the phone. Next I would look at Calling Search Space. I know you say the phones are configured the same but I would do a copy of a working phone and then just change the DN to be really sure. If I was a bettin' man I would say this is a routing issue though. The packets have to know how to get back to the VPN subnet and vice-versa. How is the data traffic doing? Any voice VLANS up?

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Re: 7940 having problems over a static VPN connection

Pings in both directions (from the VPN lan to the AVVID lan and vice versa) are fine.

In fact, I know routing works fine because I can make calls through the AVVID lan to external long distance numbers without issue.

We have no voice VLANs configured. The AVVID lan is on it's own separate subnet to avoid VLAN config issues.

The data traffic is flowing, because a reboot of the VPN based phone allows it to properly re-initialize by being able to register itself with the Call Managers. If the data wasn't flowing, it wouln't be able to even come up.

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