[asterisk-users] PJSIP ports, multiple IP addresses and wrong owner

Recursive lists at binarus.de
Sun Dec 28 10:55:41 CST 2014



On 22.12.2014 14:58, Matthew Jordan wrote:
[SNIP]
> From what I can tell in your trace, the only aspect here that may be
> incorrect is not applying the NAT'd IP address to the owner
> information. That is, in an ideal world, the owner information would
> match the IP address provided in the connection lines. Per RFC 4566,
> section 5.2, we shouldn't be sending a local IP address in the owner
> information, and it looks like we're still doing that here.
[SNIP] 
> Again, however, it'd be good to know that this is actually causing a
> problem before making an issue. Generally, most implementations don't
> assign semantic meaning to the IP address in the owner line, as the
> purpose of the owner field is to construct a globally unique
> identifier for the session, not to determine where to send media to.
> In fact, it is permissible in some situations to provide obfuscated IP
> addresses in the owner field. Again, from RFC 4566 section 5.2:
[SNIP]

In the meantime, I have tried to do some homework. I have made Asterisk bind to the main IP address of the box, and I have configured the local net and the external media address in the transport like that:

[tr_wZCMk5MvC2ATNzAr]
type = transport
protocol = udp
bind = 192.168.20.238
local_net = 192.168.20.0/24
local_net = 127.0.0.1/32
external_media_address = my.public.ip.address
external_signaling_address = my.public.ip.address

Note that Asterisk now is bound to 192.168.20.238 (this is another IP address than in my last messages).

Interestingly, these changes had a subtle influence on when the communication goes wrong, compared to the situation I have described some days ago. Since the result is the same in the end (I still can't send fax documents), I won't go into the details here. At least, we can deduce that the wrong owner line is not the only problem (if it is a problem at all which I don't believe any more).

For further analysis, I have let Wireshark create a call flow log which is here: http://www.omeganet.de/t38-call-flow-01.txt (sorry for the inconvenience, but the log is 41 kB, and the message size limit is 40 kB for this list).

I suspect that the problem is indicated by the log lines which show "T38:T30 ind:no signal". I admit that I know nearly nothing about the details of fax protocols, so I hope somebody with appropriate knowledge is willing to take a look into the log and to tell me in simple words if these lines denote a normal situation or if they denote a problem.

Thank you very much,

Recursive



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