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ipsec vpn and voip with sccp.......

i've got an ipsec vpn configured between our corporate office and a remote office. the phone in the remote office registers successfully with the callmanager server, it will ring when an internal call is placed to it but you can't hear each other. When an outside call is received or placed, you can hear successfully. what's the deal with the 4 digit internal dialing that may be preventing voice traffic from passing that an outside 10digit call is not affected by.


Re: ipsec vpn and voip with sccp.......

Based on your description of the problem it sounds like call setup between your CUCM server and IP phones are working correctly. PSTN calls to IP phones are also working. This implies that you have IP Connectivity between the CUCM/gateway and IP phone subnets. For your internal calls, you will want to ensure that your IPSec tunnel is configured to support IP traffic between the phone subnets. You will also want to make sure that there are no packet filters along the path between the phone subnets that may be inadvertently filtering RTP traffic.

Cisco Employee

Re: ipsec vpn and voip with sccp.......

The last time I saw this issue it seemed to have been caused by inspects on h323/h225 and ras. Check if your policy-map/service-policy has them enabled or if temporarily disabling them allows it to work (if so, probably want to open a TAC ticket to investigate the inspects further):

conf t



no inspect h323 h225

no inspect h323 ras


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