[Techtalk] Designing a Wireless Network

Kai MacTane kmactane at gothpunk.com
Mon Oct 15 17:49:10 UTC 2007

Hi, Everyone--

I'm looking at ways to redesign my current home network. The current 
network topology looks like the following diagram. I've capitalized the 
two main servers, just to make them stand out a bit.

[start monospaced ASCII art]

Internet ------ DSL modem --- switch -------  FINROD
               --------------------------------- wireless AP
               |         |           |
           various    Windows   workstations

[end monospaced ASCII art]

Finrod runs Web, email, DNS, and related services. Galadriel is a mixed 
machine, doing NAT/ipmasq firewalling and DHCP for the various Windows 
boxes, and also serving up MP3s and other shared files using Samba. 
(Plus she runs nightly backups of the Windows boxes, and then transmits 
those backups offsite for disaster recovery.)

Both Finrod and Galadriel are Slackware 10.2 machines.

You'll note that there's a printer currently dangling off of one of the 
Windows machines. The printer is an HP DeskJet 5740. (Since I've never 
gotten CUPS working correctly, it was simpler to just plug the thing 
into a Windows box and share it via Windows networking.)

However, there's one problem with all of the above setup: any machine 
that's connected wirelessly is on a different network segment from 
everything else. That means that not only can it not print, it also 
can't browse Galadriel's network shares, play MP3s, and so on.

I'm trying to figure out the best way to get wireless machines on the 
same network segment with everything else. So far, my ideas have included:

* Buy some kind of switch that has a WAP built in to replace the
   main internal switch (just below Galadriel in the network diagram).
   This would place everything on the same Ethernet segment.

   PROBLEM: I want at least 6 and preferably 8 wired ports available
   on that device; I'm not sure if anyone makes wireless switches
   with more than 4 wired ports.

* Put a wireless card in Galadriel. (Again, this would place every-
   thing on the same network segment.)

   PROBLEM 1: This would place the wireless antenna way down in a
   corner, where the reception might be kind of crappy. Are there
   any wireless cards that have the antenna on the end of a cable,
   so I could place it higher up?

   PROBLEM 2: Now Galadriel would have to give out DHCP addresses
   for the wireless machines as well, and I'd want to keep doing my
   current WPA-PSK authentication. Is that feature available as
   part of dhcpd, or would I need a whole new package to authenti-
   cate and manage the wireless IPs?

* Is there some kind of software voodoo that Galadriel can do to
   make packets from the WAP appear to be on the same Ethernet segment
   as the wired machines on the standard, central switch?

* Is there some other solution that's eluding me?

Ideally, all participants on the network (whether wired or wireless) 
should be able to see each other equally and access all shared network 
resources. The wired/wireless distinction should be utterly transparent, 
a moot point.

If the proposed solution requires moving the printer to Galadriel, 
that's okay... but it might result in me sending some "Help Me Set Up 
CUPS" emails to this list in a week or two. :)

                                                 --Kai MacTane
"And you can swallow, or you can spit
  You can throw it up, or choke on it
  And you can dream, so dream out loud
  You know that your time is coming 'round"

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