One way calling on first call from remote site issue

[CraigB]

Mitel 3300 (44.0.1.26) at Main site > Checkpoint VPN to Remote site > Mitel 5320e & Polycom IP 7000 phones

Remote site calls TO Main site (5320e), one way calling (I think remote site can't hear).  If Remote site hangs up and calls right back the call works properly.  If a 2nd caller from Remote site calls to Main site it works properly on first call.  After a period of time of working the one way issue will start again.
The Polycom (SIP) phones work properly all the time even when the Mitel phones don't, so this seems to be a Mitel issue.

It seems as if the Firewall/VPN may be blocking some Mitel port/protocol initially but once it's initialized it allows calls through for a period of time until it gets reset???

Does anyone have any ideas or even some general troubleshooting steps to try?

Thanks

[VinceWhirlwind]

Best is the view the Checkpoint log while the call is being initiated - any packets that are logged as blocked could be your clue.

[imanm93]

Mitel 3300 (44.0.1.26) at Main site > Checkpoint VPN to Remote site > Mitel 5320e & Polycom IP 7000 phones

Remote site calls TO Main site (5320e), one way calling (I think remote site can't hear).  If Remote site hangs up and calls right back the call works properly.  If a 2nd caller from Remote site calls to Main site it works properly on first call.  After a period of time of working the one way issue will start again.
The Polycom (SIP) phones work properly all the time even when the Mitel phones don't, so this seems to be a Mitel issue.

It seems as if the Firewall/VPN may be blocking some Mitel port/protocol initially but once it's initialized it allows calls through for a period of time until it gets reset???

Does anyone have any ideas or even some general troubleshooting steps to try?

Thanks

Make sure that you're not running NAT on your local site. NAT/firewall settings can make it impossible to initiate or receive VoIP calls altogether.