[SIPForum-discussion] SIP Header Validity

[AMIT ANAND]

On Wed, Sep 29, 2010 at 3:07 PM, usman chaudhry <usman_chaudhry at yahoo.com>wrote:

>
> Hello All,
>
> Is it possible to have a "From" header without a User Part. i.e. is the
> following "From" header format valid as per EBNF defined in Section 25 of
> RFC 3261.
>
> <sip:74.123.123.201>;tag=3482659391-3XXXXXXXX
>
> P.S
> Are there any online tools (i.e. parsers) available, using which SIP header
> validity can be checked.
>
> regards
> Usman.
>
>
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Hi Usman,

RFC2396, section 3.:
The URI syntax is dependent upon the scheme. In general, absolute
URI are written as follows:

<scheme>:<scheme-specific-part>
...............................................................................................

For our case, <scheme> is sip.
...............................................................................................

About the <scheme-specific-part>, in section 3.2.2:

section 3.2.2. speaks about the URI format:
"
URL schemes that involve the direct use of an IP-based protocol to a
specified server on the Internet use a common syntax for the server
component of the URI's scheme-specific data:

<userinfo>@<host>:<port>

where <userinfo> may consist of a user name and, optionally, scheme-
specific information about how to gain authorization to access the
server. The parts "<userinfo>@" and ":<port>" may be omitted.
"
This RFC is referenced by RFC3261 ( ref no. 5) .

As you can see clearly, the "userinfo" and "port" parts are not mandatory.
Thereby, the uri format as  <sip:hostname> is valid.

-- 
Thanks
Amit Anand
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