[Serusers] nat, symmetric /asymmetric UA....clarification needed

[Vitaly Nikolaev]

There could be clients that can use STUN to get their IP/port and NAT router
that can try to fix SIP packets. In my opinion both ways are still not good
for cutomers because of many mistakes. Please make sure that you remove all
kinf of STUN, ip autodetect from Xlite.


In REGISTER that u receiving from UA you should see private IP in Contact if
UA behind the NAT, but in location table SER should save right IP (public)
and right port (could be same or could be different depending on NAT type)

In INVITE same private contact and in SDP media address private.

IF NOT - SOMETHING TRIYNG TO FIX NAT TRAVERSAL instead of media/rtp proxy..
which is in most cases bad and need to be fixed


Make sure that if you have more then one sip UA behind the same nat you
configure different signaling and media source ports (it may be only true
for symmetric NAT but it always good to do :)


1. - yes
2. do not know what do you mean. Don't you mix symmetric media and symmetric
NAT ? first is good thing when device use same port for sending/receiving
media and second is BAD, means that .. I am not sure btw.. that NAT will use
same source port for your packets regardless.. please correct me

3. Xlite does symmetric signaling/media

4. what file ? :) I think it something mediaproxy related.. I use rtpproxy

-----Original Message-----
From: serusers-bounces at iptel.org [mailto:serusers-bounces at lists.iptel.org] On
Behalf Of Iqbal
Sent: Friday, February 25, 2005 11:30 PM
To: serusers at lists.iptel.org
Subject: [Serusers] nat, symmetric /asymmetric UA....clarification needed


Hi

Just trying to debug why some calls work and other dont, I have 2 setups,
in both the UA is xlite , and is natted in both cases...however the
routers differ in each case.

Now I am running mediaproxy, when I debug ser, in one setups the contact
header which is displayed using xlog, shows the external IP address of
the router, in the other it does not, this happens after I have passed
the fix_contact setting in ser.cfg.

The one where it is fixed , allows me to listen to voicemail prompt from
asterisk without any problems, the other...no sound.

The clarification I need is this..
1. Mediaproxy solves symmetric NAT problems with ease..Y/N ?
2. For asymmetric stuff you need to add the clients to sip/rtp-asymmetric
files Y/N ?
3 If Yes the the client in this case is xlite...which is not really the
asymmetric part, its the router in the middle is it not ?
4. If I place slite in the file, will it not then affect the symmetric
xlite also.

Now if all this fails, can I on the xlite...which seems to be behind the
asymmetric setup, use STUN server, if yes, then the mediaproxy I guess
will not get called, or should it.....or is it better to map the
port/pathsin the router itself.

As a last question, if I wanted to determine what type of NATting a
device did, or I needed to debug a customers setup, whats the easiest way

tks
Iqbal

_______________________________________________
Serusers mailing list
serusers at lists.iptel.org
http://lists.iptel.org/mailman/listinfo/serusers