binding on IPv6

[Alan DeKok]

Stefan Winter wrote:
> our production server binds to 
> 
> 0.0.0.0:1812 according to netstat.
> 
> Now I wanted to add a FR 2.0 on a specific IPv6 address on the same port,
> but that fails. I used to think these bindings should not conflict, and a
> netcat session can easily do it.

  Hmm... the opposite is possible.  i.e. listening on ::0 (v6), and
192.168.1.2.  The code in src/lib/packet.c sets the "IPV6 ONLY" flag for
IPv6 sockets.  I don't think there's a similar flag for IPv4.

  From what I understand, v4 IP's only affect v6 IP's when the v6 IP's
do 6-to-4 mapping, OR v6 is listening on ::0.

  Maybe that's wrong, but I can't find a way to force v4 sockets to not
affect v6 ones.  Just the other way around.

  Alan DeKok.