[e2e] IP options over e2e path

Xiaoming Fu fu at cs.uni-goettingen.de
Wed Mar 29 06:44:16 PST 2006

This is unfortunately (at least partially) happening: from measurements 
done by ICIR/BBN colleagues, 
over 70% connection requests with an unknown IP option were lost,
about 44% connections were broken if inserting the unknown IP option in 
the middle of transfer.

Mikael.Latvala at nokia.com wrote:
> Hello,
> The IP option provides a convinient way to add additional information to
> the IP header. But what is the fate of an IP packet, which carries a
> relatively new IP option inserted by a source host and which is not
> recognized by most of the routers and/or middleboxes that the packet
> traverses through?
> RFC1812 says that "A router MUST ignore IP options which it does not
> recognize."
> However, some people I have talked to claim that such packets with a
> relatively unknown IP option have no chance of reaching the final
> destiny.
> Is this really the case? Do new/unrecognized IP options prevent an IP
> packet from reaching its final destination? Any research papers which
> would back up or contradict this claim? Or perhaps this is yet another
> undocumented NAT feature?
> /Mikael

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