Explains the default port configuration used by Cisco vEdge devices for control and traffic connections in overlay networks.
Cisco Catalyst SD-WAN-specific port terminology is a networking configuration that uses base port 12346 for establishing connections that handle control and traffic in the overlay network.
NAT gateway considerations
NAT gateway configurations can affect port assignments in specific scenarios.
If a NAT gateway is present in the underlay and performs source port translation without preserving the original port, it may assign a random source port under certain conditions. This can occur when multiple devices are behind the same post-NAT IP address using the same source port, or if the port is already occupied by existing sessions. As a result, the assigned source port may differ from the specified range of UDP ports: 12346+n, 12366+n, 12386+n, 12406+n, and 12426+n, where n ranges from 0 to 19 and represents the configured offset. It is essential to consider this when configuring inbound firewall rules on the remote router's side.