Learning OpenStack Networking - Third Edition

VXLAN UDP port

The default port for UDP traffic between VXLAN tunnel endpoints varies depending on the system. The Internet Assigned Numbers Authority, or IANA, has assigned UDP port 4789 for the purposes of VXLAN and that is the default port used by Open vSwitch. The Linux kernel, on the other hand, uses UDP port 8472 for VXLAN. To maintain compatibility with the hosts using the Linux bridge mechanism driver and vxlan kernel module, the port must be changed from its default.

To change the port number, update the following configuration option from 4789 to 8472:

[agent] ... vxlan_udp_port = 8472

This change is typically unnecessary in a pure Open vSwitch-based environment, but is required for the environment described in this book.