Remote Call Center Agent

[newglide]

I have a remote SOHO office that is connected via VPN back to our Corporate location.
A 9611G is hanging off a CheckPoint firewall. The checkpoint is doing the VPN.
I have a 6.3 CM. The phone is currently set up h323. The user is part of a call center and uses the One X agent.
With the phone being set up as h323 I am seeing several strange issues. The user rarely has dial tone and the phone will loose registration with the CM. When it tries to re-register it takes it forever.
I have set up a lab environment using the same hardware and I can duplicate the issue.
I ran wire shark and am sifting thru it to see what is going on. I am almost 100% sure it's a firewall issue but our security guy cannot find any issues there.

As a test I set a test 9611 up running SIP. Works like a champ. Now my issue is the 9611 does not allow several of the buttons I need for the call center to work. The buttons are abrv-dial and Release. I can add them to the users buttons but they don't show up on the phone.
I know I will also have to switch to the SIP one X agent which I am in the process of testing now.
Is there another phone that I can use that will allow these buttons over SIP?

 

[rejackson]

Firewalls have options for algorithms that do things to protocols that might come inbound like h323 and sip. I have many sites with h323 phones on site to site vpns and I had to turn off the special h323 processing to get them stable. That was on Juniper Ssg firewalls. I was surprised because I thought the h323 would be hidden from the firewall inside the Vpn but it looks at it outside of the encryption.