[Serusers] nat test based on rfc1918 address in call-id field

[Richard]

________________________________________
From: Greger V. Teigre [mailto:greger at teigre.com] 
Sent: Thursday, December 02, 2004 9:00 PM
To: Richard; serusers at 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. I’d 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?