[SR-Users] Wrong Record-Route and Via header fields when TCP is used

[Leonid Fainshtein]

Hello,
The source address is correct: 192.168.0.31. I see it in tcpdump and
also in sngrep.

Thank you,
Leonid

On Mon, Jul 8, 2019 at 9:02 PM Daniel-Constantin Mierla
<miconda at gmail.com> wrote:
>
> Hello,
>
> when you look at the network traffic 9e.g., with ngrep, sngrep, ...)
> what is shown as source address for outbound leg?
>
> Cheers,
> Daniel
>
> On 08.07.19 19:21, Leonid Fainshtein wrote:
> > I just found Daniel's response to a similar question (ref.:
> > https://lists.kamailio.org/pipermail/sr-users/2019-February/104853.html):
> >
> > "check the routing rules/table of the operating systems, there should be
> > some differences between the two servers.
> > If you mhomed=1 and an unexpected interface is used for routing out the
> > traffic, it means that the operating system has internal routing rules that
> > allow going from that interface to the target address."
> >
> > Don't see anything suspicious in my server routing table:
> >
> > default via 192.168.0.1 dev eno1 proto static
> > 10.159.65.0/24 dev lxdbr0 proto kernel scope link src 10.159.65.1
> > 172.200.4.0/24 dev eno1 proto kernel scope link src 172.200.4.1
> > 192.168.0.0/20 dev eno1 proto kernel scope link src 192.168.0.31
> >
> > The request is received on the lxdbr0 interface (10.159.65.1) and sent
> > out from the eno1 interface (192.168.0.31).
> > I even tried to delete the default route but nothing helped. The
> > request is sent out with 10.159.65.1 in the via and Record-Route
> > fields...
> >
> > Best regards,
> > Leonid
> >
> > On Thu, Jul 4, 2019 at 6:20 PM Leonid Fainshtein
> > <leonid.fainshtein at xorcom.com> wrote:
> >> Hi,
> >> Kamailio server has two legs that are connected to different networks.
> >> I'm using Kamailio v.5.2.3 and the "enable_double_rr" is implicitly set to "1".
> >> The leg "A" IP address is 10.159.65.1
> >> The leg "B" IP address is 192.168.0.31
> >> The call is initiated from 10.159.65.18
> >>
> >> According to the "rr" module documentation, function record_route()
> >> should insert two "Record_Route" header fields when a request is
> >> accepted on one leg is should go out via the second leg. This works as
> >> expected in case of UDP protocol:
> >>
> >> INVITE sip:2000 at 192.168.6.106:5460;transport=UDP SIP/2.0
> >> Record-Route: <sip:192.168.0.31;r2=on;lr;did=e2c.a191>
> >> Record-Route: <sip:10.159.65.1;r2=on;lr;did=e2c.a191>
> >> Via: SIP/2.0/UDP
> >> 192.168.0.31;branch=z9hG4bKcfa5.d64ecbd87d5315b5993c4ccf16f86537.0
> >> Via: SIP/2.0/UDP 10.159.65.18:5060;rport=5060;branch=z9hG4bK3a9e9a4d
> >>
> >> But when the TCP protocol is used then the outbound message looks like this:
> >>
> >> INVITE sip:2005 at 192.168.0.178:35058;transport=tcp SIP/2.0
> >> Record-Route: <sip:10.159.65.1;transport=tcp;lr;did=bb6.7dc1>
> >> Via: SIP/2.0/TCP
> >> 10.159.65.1;branch=z9hG4bKc85a.14afc3867dd3220826f9b9940f78168f.0;i=3
> >> Via: SIP/2.0/TCP 10.159.65.18:5060;rport=58616;branch=z9hG4bK1469331f
> >>
> >> There are two problems there:
> >> a) only one Record-Route with leg is inserted
> >> b) the added "Via" header field contains the leg "A" IP address
> >> instead of expected leg "B" IP address (192.168.0.31). In the LAN
> >> trace I see that in reality the message was sent from leg "B".
> >>
> >> Is it a bug?
> >>
> >> Best regards,
> >> Leonid Fainshtein
> > _______________________________________________
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>
> --
> Daniel-Constantin Mierla -- www.asipto.com
> www.twitter.com/miconda -- www.linkedin.com/in/miconda
>