Subject: Hop-by-Hop options and Intermediate routers.

From: Syed Obaid Amin <[email-masked]>
Date: Sat, 22 Oct 2005 03:37:37 +0900

Hi

I have two inter-related issues which are unclear to me in RFC 2460. Would
anyone please clear these ambiguities?

1: If the sending node doesn't include any Hop-by-Hop option header can
intermediate router inject Hop-by-hop options?

2: If there is Hop-by-Hop option header present can intermediate router add
any new option or modify existing options?
Thanks and regards
 Obaid
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From: Francis Dupont <[email-masked]>
Date: Sat, 22 Oct 2005 09:54:01 +0200

In your previous mail you wrote:

   
=> no, it MUST NOT.

=> it MUST NOT add any new option but it MAY modify an existing option
if the option is marked as mutable en route (there is a bit in the type
to recognize such options) and only in the way defined for this option.
Note there is no such option registered by IANA today so it is hard to
give a real example...

Regards

[email-masked]

PS: look at the AH specs (RFC 2402 and I-Ds) for mutable fields in headers.

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From: Syed Obaid Amin <[email-masked]>
Date: Mon, 31 Oct 2005 07:00:02 +0900

Hi
 Thanks for your reply.

>=> no, it MUST NOT.
 It could be a part of specification ( because the problem could occur if
the packet size exeeds from the MTU ) but how can you restrict a router in
between to not change the IPv6 header.
 Thanks Again
 Obaid
 PS: Would anyone please refer any RFC or standard document where it is
mention that intermediate router can't add any option.