Discussion:
[Sip-implementors] what is the significant of IP address present in FROM, CONTACT & VIA Header
Anjan Naik
2014-08-05 09:18:05 UTC
Permalink
HI All,

Can anyone explain me ,
what is the significant of IP address present in FROM, CONTACT & VIA
Header ?

As all the header contains the same caller IP Address when INVITE being
initiated.

Thanks,
Anjan
Brett Tate
2014-08-05 09:28:04 UTC
Permalink
They don't have to contain the same values.

RFC 3261 sections 20.20, 20.10, and 20.42 describe the purpose of the
headers.

-----Original Message-----
From: sip-implementors-bounces at lists.cs.columbia.edu
[mailto:sip-implementors-bounces at lists.cs.columbia.edu] On Behalf Of Anjan
Naik
Sent: Tuesday, August 05, 2014 5:18 AM
To: sip-implementors at lists.cs.columbia.edu
Subject: [Sip-implementors] what is the significant of IP address present
in FROM, CONTACT & VIA Header

HI All,

Can anyone explain me ,
what is the significant of IP address present in FROM, CONTACT & VIA
Header ?

As all the header contains the same caller IP Address when INVITE being
initiated.

Thanks,
Anjan
Anjan Naik
2014-08-05 11:06:14 UTC
Permalink
HI Brett,

Thanks for your response.
From Section 20.10, the contact header is *Contact: "Mr. Watson"
<mailto:watson at bell-telephone.com <watson at bell-telephone.com>> ;q=0.1*
From 20.20, the from header is *From: "A. G. Bell"
<sip:agb at bell-telephone.com <sip%3Aagb at bell-telephone.com>> ;tag=a48s*
From Section 20.42, the via header is *Via: SIP/2.0/UDP
erlang.bell-telephone.com:5060;branch=z9hG4bK87asdks7.*

*If i will see all the header contains "**bell-telephone.com
<http://bell-telephone.com>**" as the domain name.*

so here my question is, why 3 times the same being display, i can make use
of this address from any one of the header.

for example, when callee wants to send request to caller, it used the
contact to send the packet, why callee cant send request based on FROM
header as both CONTACT & FROM contains the same address.

Thanks,
Anjan
They don't have to contain the same values.
RFC 3261 sections 20.20, 20.10, and 20.42 describe the purpose of the
headers.
-----Original Message-----
From: sip-implementors-bounces at lists.cs.columbia.edu
[mailto:sip-implementors-bounces at lists.cs.columbia.edu] On Behalf Of Anjan
Naik
Sent: Tuesday, August 05, 2014 5:18 AM
To: sip-implementors at lists.cs.columbia.edu
Subject: [Sip-implementors] what is the significant of IP address present
in FROM, CONTACT & VIA Header
HI All,
Can anyone explain me ,
what is the significant of IP address present in FROM, CONTACT & VIA
Header ?
As all the header contains the same caller IP Address when INVITE being
initiated.
Thanks,
Anjan
Brett Tate
2014-08-05 11:19:06 UTC
Permalink
Hi,

As I mentioned, they don't have to contain the same values.

RFC 3261 sections 20.20, 20.10, and 20.42 describe the purpose of the
headers.

The From is an identity header.

The Contact indicates where to send requests.

The Via indicates where to send responses.

The From can indicate example.com. The Contact can indicate
device1.example.com. The Via can indicates 1.2.3.4. Notice that they can
be different.

Thanks,
Brett

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