Apologies in advance for this newbie routing question...I've searched the
online docs at Cisco, read (part of) the Halabi book, etc. and just
haven't seen an answer (or something close) to this question:
Can someone tell me why I can't route a class C (or subnets thereof)
to/from my upstream provider unless I waste an address from the class C
on an interface in my router (null0, loopback, ether0, it doesn't matter).
Here's the scoop:
My upstream uses IGRP to communicate with me. Internally, I was using
RIPv1 until yesterday with static routes all over the place for
dedicated/subnet customers (of course they couldn't dial into any terminal
server accept the one assigned to them or the routing was hosed). And
yes, I had to assign an IP from each class C (we have four) to an
interface on the Cisco with that setup too ;)
Yesterday, I finally felt brave enough to setup OSPF and remove all the
static routes. I also removed the bogus IP addresses assigned to my
loopback0 (207.174.113.254/207.174.114.254) because these networks are
intended to be divvied up by our customers. When I went to bed last
night, I could ping many internal IP's from outside our network (including
207.174.113.X/207.174.114.X)...but this morning I got several calls that
"nothing was working". When I put the IP's back on loopback0, they
started working again. (If it matters, the terminal servers in our
network are Portmaster 2's and 3's running OSPF).
The Halabi book seemed to be a great book on BGP/large-scale routing, the
Huitema book seemed to be a great book on abstract routing
theory/principle, and the O'Reilly "Routing on the Internet with Cisco
Routers" seemed to be about 40% routing and 60% "other management
strategies" that are better documented in Internet Security/SNMP
Management books and wasn't of much use either. I perused the online
Cisco Internetworking Case Studies too, but (it seemed to me) none of the
examples of OSPF/RIP redistribution applied to a situation where I didn't
have an Interface *in* the network I was routing for. Isn't this
possible? Si non, pourqui pas? (sorry, I just wrote 50% of my
recollection of elementary school French in that sentence :-)
-- John-David Childs (JC612) Enterprise Internet Solutions System Administrator @denver.net/Internet-Coach/@ronan.net & Network Engineer 1031 S. Parker Rd. #I-8 Denver, CO 80231 As of this^H^H^H^H next week, passwords will be entered in Morse code.
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