Errant Proxy Behavior?

There are several things to comment on here.

I assume you're talking about a Route header value that's
not the  
topmost one (which would in most circumstances be consumed
before  
being forwarded).

Making any modification to those values while proxying is
unwise,  
even when its legal. The best way to achieve
interoperability is to  
give a proxy back EXACTLY the set of bits it record-routed
with.

Now, for the particular transformation you're describing -
it's not  
legal. Replacing a %41 with an 'A' or vice-versa would be
legal (but  
unwise). "$", on the other hand, is special.

The text in section 19.1.4 (URI Comparison) says:
...
   SIP and SIPS URIs are compared for equality
    according to the following rules:
...
       o  Characters other than those in the
"reserved" set (see RFC  
2396
          [5]) are equivalent to their ""%"
HEX HEX" encoding.

But

       reserved    =  ";" / "/" /
"?" / ":" / "" / "&"
/ "=" / "+"
                      / "$" / ","

Hope that helps,

RjS

On Nov 21, 2007, at 12:20 PM, Joe wrote:

> Hello all,
>
> If a proxy receives a message containing a SIP URI in a
Route  
> header that has "%24" in the user portion
(used as part of a token)  
> is it allowed to modify this to "$", leave
the rest untouched, and  
> forward it?
>
> This seems like incorrect behavior.
>
> Thanks!
> Joe
> _______________________________________________
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   From: Robert Sparks <rjsparksnostrum.com>

   Now, for the particular transformation you're describing
- it's not  
   legal. Replacing a %41 with an 'A' or vice-versa would be
legal (but  
   unwise). "$", on the other hand, is special.

   The text in section 19.1.4 (URI Comparison) says:
   ...
      SIP and SIPS URIs are compared for equality
       according to the following rules:
   ...
	  o  Characters other than those in the
"reserved" set (see RFC  
   2396
	     [5]) are equivalent to their ""%" HEX
HEX" encoding.

   But

	  reserved    =  ";" / "/" /
"?" / ":" / "" / "&"
/ "=" / "+"
			 / "$" / ","

Hmmmm, I agree that this is what the RFCs say, but is it
what we
really want?  That '%41' is expected to be equivalent to 'A'
but '%24'
is *not* equivalent to '$', in a context where '$' is a
character with
no exceptional semantics?  That seems like opening a big can
of worms.

Dale


_______________________________________________
Sip mailing list  https://ww
w1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use sip-implementorscs.columbia.edu for questions on current
sip
Use sippingietf.org for new developments on the application of
sip