[PLUG] Strange routing issue

[Chris Berry]

Our network is pretty small and the setup doesn't seem that complex.  The previous admin has this hackish setup where one of our remote facilities is bouncing through a file server acting as a software router.  There is no need for that as our hardware routers are perfectly capable of handling the traffic.  Here is the current setup in order: 

remote workstation (192.168.6.5 255.255.255.0 default gw 192.168.6.15) 

remote router - LAN SIDE (192.168.6.15 255.255.255.0) 

remote router - WAN SIDE (192.168.5.2 255.255.255.0) 

local edge router - WAN SIDE (192.168.5.1 255.255.255.0) 

local edge router - LAN SIDE (192.168.4.15 255.255.255.0) 

hackish software router - OUTSIDE (192.168.4.1 255.255.255.0) 

hackish software router - INSIDE (192.168.3.6 255.255.255.0) 

core router - (192.168.3.1 255.255.255.0) 

local workstation - (192.168.3.76 255.255.255.0 gw 192.168.3.1) 

That all works fine as currently setup. 

So the other night we went to do maintenance and remove the software router.  We changed the local edge router address from 4.15 to 3.230 and added the RIP info on the core router.  At first it seemed fine, the routes all got shared, however after a bit our testing showed that we could get to 6.15 on the remote router, but that we couldn't reach 6.5, in fact even the remote router couldn't reach 6.5 (from within a remote session) which is strange since that's on the same subnet.  We rolled back the changes and everything is fine, but I have to admit I'm a bit puzzled.  Can I buy a vowel? 
Chris Berry
Linux Systems Administrator
Davis Tool
x521