D'oh!

[Lennart Sorensen]

On Sun, Jan 20, 2008 at 04:29:41PM -0500, James Knott wrote:
> ????
> 
> My router (a linux box) has a real world address. The modem has a
> 10.x.x.x address. Rogers uses addresses in the 10.x.x.x range for
> communications around it's internal network. Fox example, if I do a
> traceroute to Yahoo, I get these lines, plus a few more at the Yahoo end.
> 
> 1 10.11.0.1 7.082 ms 6.737 ms 5.814 ms
> 2 vl-201.gw03.wlfdle.phub.net.cable.rogers.com (66.185.90.161) 9.586 ms
> 9.075 ms 11.881 ms
> 3 te-15-1-0.gw01.wlfdle.phub.net.cable.rogers.com (24.153.5.25) 7.223 ms
> 10.299 ms 9.148 ms
> 4 so-2-3-0.gw02.bloor.phub.net.cable.rogers.com (64.71.240.106) 6.814 ms
> 9.930 ms 8.484 ms
> 5 so-1-1-0.igw01.chcrmk.phub.net.cable.rogers.com (66.185.80.201) 18.428
> ms 21.458 ms 18.615 ms
> 6 * * *
> 7 so-1-0-0.pat2.nyc.yahoo.com (216.115.101.159) 42.667 ms 38.064 ms
> 33.467 ms
> 
> Notice that address in line 1? That's the next hop beyond my modem address.
> 
> Many people believe the RFC1918 addresses are non-routable, which is
> nonsense. They route just fine, but are not supposed to be routed onto
> "The Internet". So, Rogers uses them internally and should be filtering
> them, to keep them from going to the internet. The same thing happens
> with ADSL DSLAM's.

Oh they are routeable, but only within a private network.  Rogers can
use private IPs internally in their network for devices which noone
outside rogers should ever talk to directly.  As long as rogers knows
how to route it, everything is fine.  The IP they assign to the customer
obviously has to be routeable on the internet and not just rogers
network so it has to be a non private IP.

--
Len Sorensen
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