[arin-ppml] ARIN-prop-127: Shared Transition Space for IPv4 Address Extension
jbates at brightok.net
Thu Jan 20 18:20:18 EST 2011
On 1/20/2011 4:28 PM, George, Wes E [NTK] wrote:
> 1) ISP assigns the same block of 1918 space to the external interface as is
> already in use on the internal interface of a customer's home GW router and
> badness ensues.
For many years (the last isolated network was finally cleaned up 2 years
ago), different sections of the telco networks I manage used RFC-1918
and PAT. The last one was a 300+ subscriber wifi service, which
renumbered into real IPs when they changed out wireless hardware on the
towers a few years ago.
Reasons the PAT went away were standard troubleshooting/tracking issues,
as well as load on the routers (they were low end software based
routers). Largest complaint was breakage of VPN/ipsec software which
wouldn't (or they didn't know how to make it) do NAT-T. In one case, NAT
went away as I upgraded the router to a code which wouldn't support NAT. ;)
For the record, we almost exclusively used 10.0.0.0/20 or longer in
these environments. Problems with customer router conflicts was the
smallest of problems introduced by using NAT.
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