IP backbone numbering/naming

Sat Nov 16 05:15:01 UTC 2002

haesu at towardex.com wrote:

> You could also use RFC1918 numbers for your point-to-point /30 
> aggregation blocks with the customers.. But.. since that would have 
> effect on customer's premise equipment, it would be better to give 
> them globally unique space as well, who knows if your customer comes 
> back and yells at you for not being able to get to his router's serial 
> interface IP.
>

This practice was implemented here in the early days, before I came 
along. There have been almost no requests to change by clients, and 
very, very few who even noticed/cared enough to ask why.

But as more VPNs are deployed, I've seen this break some 
implementations. So for two reasons we've begun the (large) task of 
renumbering all the /30 ptp links either public or unnumbered:

1) Ensures all clients who decide to implement VPN don't run into 
frustration because of this practice. We want to encourage better 
security practices, and VPN can be an integral part of that.

2) The script kiddies won't mistakenly assume that we're not doing 
source address filtering. I'm sure that seeing a private address in 
traceroute probably makes you a more desirable target in certain circles.

There is only one case where I would recommend using a private address 
on a public link. We have a client periodically attacked, and in some 
cases the attackers have simultaneously attacked our own infrastructure. 
They now have only one path to them here, and every hop past the border 
is RFC1918.