[15212] in North American Network Operators' Group
Re: ISPs Blocking Private Addresses?
daemon@ATHENA.MIT.EDU (Jay R. Ashworth)
Mon Feb 9 19:24:38 1998
Date: Mon, 9 Feb 1998 19:11:42 -0500
From: "Jay R. Ashworth" <jra@scfn.thpl.lib.fl.us>
To: "'nanog@merit.edu'" <nanog@merit.edu>
In-Reply-To: <Pine.SOL.3.96.980209143657.2134B-100000@vellocet.insync.net>; from Joe Shaw <jshaw@insync.net> on Mon, Feb 09, 1998 at 02:42:19PM -0600
On Mon, Feb 09, 1998 at 02:42:19PM -0600, Joe Shaw wrote:
> Most people use what's commonly refered to as Martian filters to filter
> out private address spacing. It allows those ISPs to use private address
> space internally and not have to worry about advertising them via external
> routing protocols and also keeps them from accepting bogus route
> announcements from other providers who haven't used the filters.
There's an important distinction to be made, Joe, betwen filtering
_packets_ and filtering _announcements_. Martian filters usually
filter packets. What you announce, and what you send, need not have
anything to do with one another.
> > Do the "default-less" ISPs filter private addresses or do they let
> > routing/forwarding do the work?
>
> Default-less?
Yes: backbones whose routers have no default place to send packets not
handled by some explicit route.
Cheers,
-- jra
--
Jay R. Ashworth jra@baylink.com
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