Re: Routing 10.0.0.0 through Linksys router to my Cisco DSLmodem?
From: Michael Buchenrieder (mibu_at_scrum.muc.de)
Date: Wed, 4 Aug 2004 06:33:26 GMT
email@example.com (Kevin) writes:
>David Efflandt <firstname.lastname@example.org> wrote:
>> The only way you could possibly connect from PC to Cisco config would be
>> if the Linksys to Cisco connection was using ethernet tcp/ip AND you could
>> set a static route for that IP on the Linksys WAN.
>This is hard for me to understand, not being a heavy networking
>type. All TCP/IP traffic out of the Linksys goes through the
>Cisco, and there is only one connection between the Cisco and the
>Linksys. Why would the Linksys be confused on where to route
>10.0.0.X packets when it passes packets bound for all other
>destinations? I'm not trying to be obstinate; I'm just ignorant
>about this and want to understand better.
The problem is that the 10.x.x.x network is on a non-routable
address range. Therefor, no router should let pass these addresses
out through a standard (routable) IP address, unless it does have some
rather advanced rulesets in place. Example: It is quite common for
ISPs to use addresses of that range internally, thus reducing the amount
of routable addresses needed for their own (internal) network.
Typically, you'll then see, e.g., their DNS servers using such addresses.
A standard router, however, doesn't typically include such advanced
routing capabilities, and will simply drop outbound packets from
reserved ranges - for good reasons. Furthermore, you'd still need
to configure the Cisco with a route back to the 192.168.x.x network
for to be able to communicate with it. While this _could_ be done
via some workarounds (create a tunnel or whatever), the whole setup
is really, really broken. Connect the Cisco directly to a separate PC
only used for configuring the Cisco.