Need Help with Expressway Firewall Ports

[chuck.brule]

OK So I think I understand how the firewall traversal works except for one thing:

Media between the Expressway/VCS-E and the Control/VCS-C is only open in one direction according to the instructions. This feels like it isn't going to work.

Am I missing something here?

Chuck

[Anesh Ramauthar]

Can you provide which document and software versions you are enquiring about?

[marcuscsg · Accepted solution]

Hello Charles,

The communication is bidirectional.  Expressway C sends an HTTPS request to Expressway E using certificates and this stream stays open because Expressway C continues to send keep alives.  T

I believe what you are looking for is on page 7 of the deployment guide if you are using the newer Expressway C/E architecture.

http://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/expressway/config_guide/X8-7/Cisco-Expressway-IP-Port-Usage-for-Firewall-Traversal-Deployment-Guide-X8-7.pdf