Re: Who does source address validation? (was Re: what's that smell?)

[Iljitsch van Beijnum <iljitsch () muada com>]

On Thu, 10 Oct 2002, Jared Mauch wrote:

[People using RFC 1918 addresses for routers that terminate tunnels which
breaks path MTU discovery when RFC 1918 source addresses are filtered
elsewere.]

>       People number out of 1918 space primarily for a few
> reasons, be them good or not:

>       1) Internal use
>       2) Cost involved.. nobody else needs to telnet to my p2p
> links but me, and i don't want to pay {regional_rir} for my
> internal use to reduce costs

So use IP unnumbered.

>       3) "security" of not being a "publicly" accessible
> network.

Well then they get more security than they bargained for if their network
becomes inaccessible...

>       With the past scare of "we'll be out of ip addresses by 199x"
> still fresh in some peoples memories, they in their good consience decided
> to also conserve ips via this method.