[asterisk-users] Realtime SIP, multiple AX servers question

[Tilghman Lesher]

On Tuesday 04 January 2011 09:40:56 Bryan Field-Elliot wrote:
> Thanks Olle.  Do you suppose I am the first Asterisk user to discover
> this behavior? I would find that hard to believe that I'm the first
> person to notice...

It wasn't designed to do this.  While you can have the same sippeers table
for multiple servers, you really should have a separate sipregs table for
each backend server.  The reason why is that some mappings depend
implicitly on the host to which it was registered.  For example, if a phone
is behind a NAT, then the external port is dependent upon the same host
responding.  If a different host tries to communicate to that external port,
some NAT devices will not route the packet properly.  This is especially
true for SIP over TCP, but it's also true for UDP packets.  (Routing
packets back through a NAT without verifying the sending IP is a security
risk.)

Probably more appropriate for your case is to use DUNDi to coordinate your
machines as to which server presents holds the registration for any
specific phone.

-- 
Tilghman