hi
Indeed dialog OPTIONS are send with wrong CSeq and there is no way to fix
it without patching source.
In docs for dialog module "If keep alive is enabled for a dialog, the
module will send SIP OPTIONS requests with CSeq lower or equal than last
request within dialog"
Usually Kamailio is used before some media server (asterisk, freeswitch...):
endpoint1 - kamailio ----leg1---- media_server ---leg2---- kamailio -
endpoint2
So if it is your case and you want to check if dialog alive, you may ping
media server instead of pinging remote endpoints:
for leg1: dlg_set_property("ka-dst");
for leg2: dlg_set_property("ka-src");
Of course your media server should support this not inaccurate CSeq
handling. I successfully use it with freeswitch for example (with some
minimal freeswitch tuning)
2018-04-12 23:34 GMT+03:00 Oded Arbel <od...@cloudonix.io>:
> Hi all.
>
> I'm trying to use the dialog module's keep alive feature (ka_interval()
> and dlg_set_property()), and the documentation (under dlg_set_property)
> says this:
>
> If keep alive is enabled for a dialog, the module will send SIP OPTIONS
> requests with CSeq lower or equal than last request within dialog
>
> This is seems really weird to me, but the problem is worse than that -
> when setting dlg_set_property("ka-src"), the OPTIONS messages sent to the
> caller always have CSeq set to "0", regardless of what CSeq the UA sent on
> its invite.
>
> The problem is that while some UAs respond to these purposefully broken
> messages with some kind of a 5xx reply (for example, Linphone funnily sends
> "500 Internal Server Error"), several UAs don't respond at all. Worse than
> that - some of the UAs that send back 5xx replies to OPTIONS with a
> non-zero but invalid CSeq will completely ignore the OPTIONS keep-alive
> message that is sent to the caller with a CSeq 0 - for example, PJSIP
> responds with "503 Invalid CSeq" to a "ka-dst" OPTIONS message but will
> ignore a "ka-src" OPTIONS message with CSeq 0.
>
> My questions:
> 1. Why are keep-alive messages sent with a wrong CSeq?
> 2. If we're keeping the "wrong CSeq" approach, can we at least not send
> CSeq "0"?
> 3. Is there a way to change any of the above behaviors with a
> configuration (i.e. without patching the sources)?
>
> Thanks in advance
>
> --
> Oded Arbel
> od...@cloudonix.io
>
>
>
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>
--
Savolainen Dmitri
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