[asterisk-dev] Virtual IP Adresses and SIP requests failing...

[King Ho]

Hi,

Sorry about responding to this after such a long time has past from the last
post but I have just recently encountered the same problem with having
multiple IP address assigned to a single interface and have problem with sip
client registering to asterisk if asterisk uses bind=0.0.0.0.

I think what Tilghman said is not exactly correct. That is, asterisk will
not be able to control how the packet is routed BUT asterisk DOES have
control of which IP address the response uses for the "source ip address" of
the packet. That is, if I send a sip register request to asterisk at address
x.x.x.x, I expect asterisk to response using the same x.x.x.x address as the
source ip address in the response, even though asterisk won't be able to
control how the packet is routed.

If program don't have control over which IP address to use in the source
address in the response, then I think a lot of programs like Bind, the DNS
server, will fail when they are bound to multiple ip addresses.

I do think that this is a bug in the handling of the response packet's
source ip address.

Best Regards,

King

> -----Original Message-----
> From: asterisk-dev-bounces at lists.digium.com
> [mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of Tilghman
Lesher
> Sent: Monday, May 07, 2007 1:53 AM
> To: Asterisk Developers Mailing List
> Subject: Re: [asterisk-dev] Re: Virtual IP Adresses and SIP requests
failing...
> 
> On Sunday 06 May 2007, Christopher Aloi wrote:
> > On 5/5/07,  Tilghman Lesher <tilghman at mail.jeffandtilghman.com> wrote:
> > >  On Saturday 05 May 2007, Sergey Okhapkin wrote:
> > > > Yes, it's the expected IP stack behavior when the service is bound
to
> > > > 0.0.0.0. Asterisk sends the repy to the address from which the
> > > > request came, it has no control which src address to use.
> > >
> > > Actually, it does control it; it uses the Linux routing map to select
> > > which address it uses as its source address.  There has been a request
> > > for some time to allow Asterisk to reply on the same address on which
> > > it received packets, but I don't know that there's been any successful
> > > patch so far.  You're certainly welcome to add your efforts to getting
> > > Asterisk to do that, though.
> >
> > So what your saying is that my ultimate goal (2 ip's on different
> > networks) is obtainable; but that I should be looking into my route
table
> > and not Asterisk, am I following correctly?
> 
> Specifically, you should be using two separate network interfaces, one for
> each network.  Multi-homed is supported today.  Multiple addresses per
> interface is not.  Only the primary address on each interface is used, and
> we use the routing table to determine on which interface to send a packet.
> 
> >  I wasn't able to find a bug report indicating this behavior, do you
> > think this is something I should open for review?
> 
> It's not a bug; it is simply a feature we haven't fully implemented yet.
The
> problem is that this is not easy to accomplish, and it seems that every
> platform does it differently.
> 
> --
> Tilghman
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