[clue-tech] Installing new router, getting printer to work

[David L. Anselmi]

Adrian F. Nagle, IV wrote:
> Thank you Dave.  All of your assumptions are correct.
> 
> I have since set the new router to a "Bridge" setting.  It picks up
> 192.168.0.67.  If I put the printer back to a static address of
> 192.168.0.6 and reset the CUPS definition accordingly, it works.

By telling it to bridge you essentially turn it into a switch so you're 
back to one logical LAN segment (that is, everything is on the same 
192.168.0.0/24 subnet).

Honestly, that's the easiest arrangement and so probably best unless you 
want to experiment with routing.  I think networking is fun but if you 
aren't educating yourself on it I think you'll just be frustrated by the 
added complexity.

> So, if I wanted two LANs to work, what definitions do I have to look
> at?  I'm perusing the router settings and I do not yet see and NATs
> rules to add or work with.  If the router is in router mode, I get a
> routing table.  Incidentally I see now also that there is a feature
> for Dynamic routing "RIP: Disabled".  Perhaps this should be set to
> one of the options listed as "LAN & Wireless"?

Typically SOHO "routers" have a sense of "LAN" and "Internet" and they 
do NAT between them.  That way the router only uses one IP address on 
the Internet side, which is what your DSL modem is doing.

NAT is a little like a check valve.  Things flow out to the Internet 
smoothly but they have a hard time coming back in from the outside (I'm 
talking about connections, not the actual packets, which go both ways of 
course).  My assumption was that you have that kind of router so NAT was 
tripping you up.  Maybe I as wrong.

If you have NAT you might see something called "port forwarding".  On my 
Linksys I have an Applications & Gaming tab that has port forwarding and 
port triggering sub-tabs.

If you don't have NAT then you have to tell the 0.0 network what gateway 
to use to get to 24.0.  If your wireless devices can get to the Internet 
I'd bet you have NAT, so that's where your issue is.  Explaining the 
routing if you don't have NAT is a little long for an email (there are 
lots of things to read on the 'net).

If you want to test whether you have NAT you can run tcpdump on the 
server and ping it from your laptop.  In the output you'll see, the 
destination IP will be that of the server.  The source IP, if it's 0.x, 
is that of the new router (on that side of it--your picture only shows 
one IP for the new router but it has two, one on each LAN).

HTH,
Dave