Looking for an IPv6 naysayer...

Scott Helms khelms at ispalliance.net
Wed Feb 9 15:50:39 CST 2011


On 2/9/2011 4:36 PM, Ken A wrote:
>
>
> 10/8 is the management network on my cable modem. The cable modem 
> bridges your wan 'real' ip(s) through to your PC or router. At least 
> that's how Suddenlink does it here. The customer is normally 'locked 
> out' of the cable modem, unlike a dsl modem. The largest NATs are 
> presumably w/mobile carriers. I've never been behind NAT (except one I 
> controlled) on a consumer dsl or cable link in the US.
> Ken
>

Agreed on the cable side (DOCSIS at least) but most of the DSL systems 
I've seen are doing NAT on virtually all of the end user gear.  Bell 
South, SBC, Verizon, and Pac Bell are all doing or in the recent past 
did most/all of their DSL installs this way.  Bell South tried using a 
brouter (only one I've seen in the wild) that did PPPoE on the WAN side 
and then handed out the same address it was assigned via DHCP on the LAN 
interface, but it was problematic (imagine that) and they stopped using 
it some years before the AT&T purchase/merger.

The smaller telcos are almost universally doing NAT as well providers 
like Alltel, Centurytel, Frontier, Finepoint, as well as the smaller 
ILEC's simply don't do bridging on their CPE gear since they seldom had 
their DSLAMs set up to deal with Q-in-Q or isolation methods.  That's 
not to say I don't know some that are the exception since I do know of a 
few telcos that run PPPoE clients on the client PC and a handful that 
did get port isolation working but they are not the norm in the US.

-- 
Scott Helms
Vice President of Technology
ISP Alliance, Inc. DBA ZCorum
(678) 507-5000
--------------------------------
http://twitter.com/kscotthelms
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