Subject: Re: [Patch iproute2] vxlan: use 8472 as default dst port

From: Stephen Hemminger <[email-masked]>
Date: Thu, 16 May 2013 09:02:39 -0700

On Thu, 16 May 2013 09:24:47 +0100
"David Laight" <[email-masked]> wrote:

> > > From: Stephen Hemminger <[email-masked]>
> > >
> > > I want all new users to get the IANA port without asking.
> > > Old users with existing nets have to force the port to the one they
> > > were using.
> > 
> > That'd be great -- what we're getting is all new users are getting
> > a listen port of 8472 and a send port of 4789. So new users who aren't
> > aware of why will simply see that two *new* installations don't talk
> > to each other (and never will, using default ports, because the kernel
> > and ip will need to be compatible with their incompatible selves).
> 
> Could the kernel listen on both port numbers?
> Then the default 'send' port could be changed while maintaining
> functionality for existing systems.
> 
> At some later time the listener on 8372 could be removed.
> 
> 	David
> 
> 
> 

Actually with the destination port per vxlan it is possible to do.

1. Create vxlan0 with old port number
2. Create vxlan1 with new port number
3. Create a bridge vxlanbr0
4. Put both vxlan's into the bridge

Then the bridge will silently handle finding the correct port
and allow migrating other hosts to the new port number.