On Fri, May 26, 2017 at 04:04:24PM -0700, David Ranch wrote:

Hey Brian, What about configuring an ICMP direct on the old IP to point to the new IP? --David KI6ZHD

Well, after thinking about it a bit and reading the relevant RFCs, I thought I'd give it a try and wrote some code in the router daemon to do this.

Unfortunately, the FreeBSD kernel prohibits a user-space process from sending ICMP Redirects - you get 'Permission denied' errors when you attempt to write one to the outgoing ICMP socket.

Too bad, it would have been an interesting experiment.

Maybe there's some way to fiddle the routing table so that the kernel itself sends them. I'll look into it, but a quick peek into the kernel source suggests it's not doable. - Brian