Not sure this is the correct forum for this question.
Is there any documentation or hints on configuring a Meraki MX firewall to support an Expressway-E Dual Nic configuration to have it talk to the outside and to the Expressway-C on the inside?
Typical deployment is LAN1 connected to "Transit DMZ" separated by firewall between internal network, including Exp-C server and LAN2 connected to "Services DMZ" which is either using public addresses (rarely) or doing static NAT (most common). As a side note NATing on LAN1 (transit DMZ) is not supported.
For port usage you can refer to the following link:
As far as Expressway is concerned you may refer to the following for Dual NIC configuration on Expressway E:
http://www.cisco.com/c/en/us/support/docs/unified-communications/expressway-series/117811-configure-vcs-00.html#anc14
Typical deployment is LAN1 connected to "Transit DMZ" separated by firewall between internal network, including Exp-C server and LAN2 connected to "Services DMZ" which is either using public addresses (rarely) or doing static NAT (most common). As a side note NATing on LAN1 (transit DMZ) is not supported.
For port usage you can refer to the following link:
http://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/expressway/config_guide/X8-1/Cisco-Expressway-IP-Port-Usage-for-Firewall-Traversal-Deployment_Guide-X8-1.pdf
If you are specifically looking for Meraki Firewall Configuration only then you can post this question in firewall forum.