Agent instance fails to start with IPSec enabled


I am having trouble spawning containers when running a rancher agent on a server with IPSec enabled. When I start the container, I see this in the logs:

APIError: 500 Server Error: Internal Server Error ("driver failed programming external connectivity on endpoint e3d55e88-6ba7-481f-9bb8-484a2b7948c0 (c4f4539de9660e45a3a5c6b064ca1c0dd761a5528f5971f24a537c5560cd360d): Error starting userland proxy: listen udp bind: address already in use")

It’s true that port 4500 is already used by IPSec.

How can I allow rancher to start containers while running IPSec? The Rancher server and agent can communicate just fine over IPSec - I just can’t spawn new containers. Any ideas?

BTW - I’m running Ubuntu 16 with Docker 1.12.

Seems very similar to this post: Network Agent fails to start

This is a feature request: