Calls droping after 50 sec

[snorri.kristjansson]

I have a setup using VCS and Expressway, my endpoints are registered and serach rules and zones are in place. At the moment I can make outbound calls and answer inbound calls. I also have a C40 connected to a public IP and not registered to the expressway nor the VCS but it is on the same subnet as the Expressway.

Now this is my problem all calls that are routed throght the firewall will drop after 50 sec exept the calls to my test C40. These calls are routed throgh the wall the same way as any others with the exeption of the codec beeing on the same subnet.

We have been looking at the trafic but I cant figure out where themproblem is... Any good ideas?

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[Martin Koch]

Let me guess the call you are placing is via h323 or sip/udp/tcp? Does it behave different if the call is all the

way through an encrypted sip call (tcp/5061/tls)?

Either your firewall still blocks some ports (see the vcs admin guide and

http://www.cisco.com/en/US/docs/telepresence/infrastructure/vcs/config_guide/Cisco_VCS_IP_Port_Usage_for_Firewall_Traversal_Deployment_Guide_X4_to_X7.pdf )

or, even more likely you have some enterprise grade firewall with inspection, h323/nat helper

or application layer gateway functionality.

Anything what is changed within the payload of the voip pakets (sip, h323, rtp, dns, ...) has to be

disabled, most enterprise firewalls have such features enabled by default.

Less likely are some very low set tcp timeouts.

[snorri.kristjansson]

Yes, we do indeed have a enterprice firewall, I need to look into Sip as you are right we are using h.323. Thanks, I will keep you updated.

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[snorri.kristjansson]

It looks like the problem was with layers in the firewall.

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