[90406] in North American Network Operators' Group
RE: private ip addresses from ISP
daemon@ATHENA.MIT.EDU (Brian Johnson)
Tue May 23 11:25:12 2006
From: "Brian Johnson" <bjohnson@drtel.com>
To: <nanog@nanog.org>
Date: Tue, 23 May 2006 10:22:35 -0500
In-Reply-To: <447326ED.6090702@ttec.com>
Errors-To: owner-nanog@merit.edu
> -----Original Message-----
> From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On
> Behalf Of Joe Maimon
> Sent: Tuesday, May 23, 2006 10:15 AM
> To: Robert Bonomi
> Cc: nanog@nanog.org
> Subject: Re: private ip addresses from ISP
>
>
>
>
> Robert Bonomi wrote:
>
> >
> > TTL-E messages _do_ have legitimate function in network management.
> > TTL-E messages _can_ originate from RFC1918 space,
> addressed to 'public
> > internet' addresses. Usefully, and meaningfully. Ever
> hear of 'traceroute'?
> > Ever use it where packets went across a network using
> RFC1918 internally?
> > Ever had a route die _between_ two RFC1918 addressed nodes
> on somebody elses
> > network?
>
> I guess this means that providers who utilize rfc1918 along
> their hops
> should make an effort to ensure these addresses are not used for icmp
> messages or translate these addresses when they source icmp.
>
> Understandably, translation on providers networks is not
> always feasible.
>
> A feature on routers that sourced icmp packets to be told specificaly
> which address of the router to source it from would also help.
In the Cisco world, I thought that the source would always be the interface
that replies to the ICMP packet. That seems to be good form to me.
Where am I going wrong?
>
>
