[asterisk-users] chan_sip sending from wrong source address when multiple interfaces are used

[Alec Davis]

I've seen similar.

We tried 4 interfaces. On 4 lans, are these considered to be overlapping?
192.168.1.1
192.168.2.1
192.168.3.1
192.168.4.1

I tried this months ago on 1.8, and set provisioned phones to register with
asterisk interface on the lan they were on.
The phones won't register, we're un-responsive, 60 of them.

Removed the bindings, and left only one.
Reprovisioned the phones again, all 60 of them. All is well.

Have I tried again. No.
Did I have enough time to debug. No.
Sorry.

Alec Davis
 

> -----Original Message-----
> From: asterisk-users-bounces at lists.digium.com 
> [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of 
> Kevin P. Fleming
> Sent: Thursday, 12 July 2012 2:28 a.m.
> To: asterisk-users at lists.digium.com
> Subject: Re: [asterisk-users] chan_sip sending from wrong 
> source address when multiple interfaces are used
> 
> On 07/11/2012 07:51 AM, Olle E. Johansson wrote:
> >
> > 10 jul 2012 kl. 20:50 skrev Kevin P. Fleming:
> >
> >> On 07/10/2012 03:24 AM, Olle E. Johansson wrote:
> >>
> >>> The Asterisk SIP channel has no knowledge about 
> interfaces and can't 
> >>> bind to a specific interface for communication. In fact, 
> it's a well 
> >>> known bug that if you have multiple interfaces with different IP 
> >>> networks, Asterisk will send from the wrong IP on some of 
> the interfaces.
> >>
> >> Are you sure about that? The only problem area that I'm 
> aware of is when there are multiple *overlapping* interfaces 
> (on the same subnet, or providing the same route(s)). In that 
> case, Asterisk can receive messages on one IP address out of 
> the overlapping set, but reply using a different one from the 
> set, because it doesn't specify the source IP address and 
> instead lets the UDP/IP stack select one.
> >>
> >> If the interfaces don't overlap in any way, I don't see 
> how it would be possible for Asterisk to send messages with 
> the wrong source IP address, since it does not specify the 
> source IP address at all. If this is occurring, it must 
> involve the operating system's IP stack in some fashion.
> >
> > Yes, I still use quite a lot of IPtables tricks to overcome 
> this issue.
> 
> That's quite interesting; can you describe a scenario where 
> this occurs?
> 
> --
> Kevin P. Fleming
> Digium, Inc. | Director of Software Technologies
> Jabber: kfleming at digium.com | SIP: kpfleming at digium.com | 
> Skype: kpfleming
> 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA Check us 
> out at www.digium.com & www.asterisk.org
> 
> 
> 
> --
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