Cisco Expressway IP Port Usage CMS Web Proxy Ports & Firewall Questions

[Anas Hafez]

I have been reading in the below guide:

https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/expressway/config_guide/X12-5/Cisco-Expressway-IP-Port-Usage-for-Firewall-Traversal-Deployment-Guide-X12-5.pdf

And I'm having some questions regarding deploying CMS Web Proxy using Expressway:

• I'm having trouble understanding these 2 Lines and the public IP talk to the private or itself and why does the expressway does this

• Does the below lines mean that there's no need to allow these ports on firewall or only the NAT reflection feature:

• Does opening the below ports on the external firewall have any risk from the security perspective and is it mandatory

• Is deploying CMS with single Edge supported with the below deployment

External Firewall --> Expressway Edge (Dual NIC) --> Internal Firewall-1-->  Expressway Core --> Internal Firewall-2--> CMS