3 Dec
2004
3 Dec
'04
2:32 a.m.
________________________________________
From: Greger V. Teigre [mailto:greger@teigre.com]
Sent: Thursday, December 02, 2004 9:00 PM
To: Richard; serusers(a)lists.iptel.org
Subject: Re: [Serusers] nat test based on rfc1918 address in call-id field
If I understand you correctly, you are talking about
test 16 found in
nathelper cvs.
You may want to have a look at that test first. You
call
nat_uac-test("19") to
trigger the test.
g-)
eh
test 16 is different
it tests if the source port is different from the
port in Via.
The proposed test checks the private ip in Call-ID field.
> Hi,
> I am thinking about having more NAT test on a sip packet. Just want
> to find out if it is useful.
> I run into some situations that some smart UAs try to detect its
> external IP and put the external IP address into the sip packet.
> Depending on the network and NAT firewall setup, it may or may not
> set the right external IP and port in the packet. If it is not, but
> pretends to be on the public internet, then there is most likely a
> one-way voice or no voice issue. Id like to be able to detect and
> force it to use a nat proxy. By checking these packets, I found that
> the only trace is the private IP address in the call-id header field.
> It will be useful to check if a RFC1918 address is used in the
> call-id. I understand that it is not a thorough test for NAT, well,
> just like any other NAT test.
> Can someone please comment if it is a good test?