Re: If you have nothing to hide

[Eric Osborne <eosborne () cisco com>]

> Validation of routing policy to ensure others aren't abusing you (pointing
> default, for example). As for orders of magnitude, once an IP option is
> in a packet, the damage is essentially done, otherwise looking up the
> path to an address in the options is no more impactive than looking up the
> address in the original destination field. 

Well, no.  Not really.
First off, following the 80/20 rule (or in this case 99.x/(100-99.x)
rule) says that hardware implementations which get optioned packets
punt them to software.  This is at every hop.

Second, the IP source route is a stack of IP addresses, which must be
modified at every hop.  This implies not just software forwarding, but
also significantly more work than an IP lookup.




eric

> source-routing only has security
> implications to those with defenses which permit traffic through some type
> of backdoor. The backdoor has more security implications than the
> source-routing, since it may be compromised in other manners.