Re: alternatives to private RFC-1918 addresses on public routers

[Daniel Senie <dts () senie com>]

William Allen Simpson wrote:
> When I complain, I prefer to suggest alternatives.  In this case, the
> two that come to mind are:
>
>  1) unnumbered interfaces.  I've used these with PPP for years, but as
>     I remember, there was a problem with Ciscos.  Has this been fixed?

I've used them in several deployments, and they work just fine. You do
need at least one local interface with a real, public address to do
this. When configuring the unnumbered interface, you specify which other
interface (e.g. an Ethernet, or probably even a loopback) to use for IP
address when needed (for ICMP messages and such).

>  2) host routes.  Rather than creating /30 subnets for links (wasting
>     2 addresses for each 2 used on a link), go all the way and use /32
>     for each address.  This make the local routing table a bit bigger,
>     but the entries are rarely used, and aggregated at the boundaries.
>
> Thoughts?
>
> Isn't there a link around somewhere on this?
>
> What about a link for bogon filters to use at boundaries?
>
> WSimpson () UMich edu
>     Key fingerprint =  17 40 5E 67 15 6F 31 26  DD 0D B9 9B 6A 15 2C 32


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Daniel Senie                                        dts () senie com
Amaranth Networks Inc.            http://www.amaranthnetworks.com