On the Expressway-C traversal client zone, the peer address should be the Expressway-E public IP address in a single-NIC deployment and the Expressway-E internal NIC address in a dual-NIC deployment; the wrong address can stop ACKs from Unified CM reaching the edge.
Checked 2026-09-25
- Vendor
- Cisco
- Product
- Cisco Expressway
- Subsystem
- traversal zones
- Deployment
- on-premises
- Region
- not restricted
- Release range
- written against X8.x; not re-validated on X15
- Checked
- 2026-09-25
Sources
- Troubleshoot Most Common Issues for Business to Business Calls Through Expressway — Cisco Systems · tier 2 current vendor documentation · Issue: ACK not forwarded to the Expressway-E
Cite this note
APA
WarmTransfer. (2026, September 25). Setting up business-to-business calling on Cisco Expressway: source note expressway-b2b-setup-traversal-peer-address-nic. WarmTransfer. https://warmtransfer.net/knowledge/claims/expressway-b2b-setup-traversal-peer-address-nic
BibTeX
@misc{warmtransfer-claim-expressway-b2b-setup-traversal-peer-address-nic,
title = {Setting up business-to-business calling on Cisco Expressway: source note expressway-b2b-setup-traversal-peer-address-nic},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/expressway-b2b-setup-traversal-peer-address-nic},
note = {Source note expressway-b2b-setup-traversal-peer-address-nic, checked 2026-09-25}
}