Use WiFi as an Ethernet bridge to the Internet?

I want to get a Comcast cable internet connection and use WiFi to use the
network in a computer room about 30 feet away. This doesn't seem to pose a
big problem in theory, with one frame-and-drywall and one short adobe (~42
inch-high mud brick) interior wall obstructing the line of sight between
the cable connection and the PC. Because I have no Windows, just Linux, I
would like to support Linksys' release of software in their WRT54GL
"broadband router" and Windows-only software is useless to me.

I understand the basics of IP networking but I'm having trouble
understanding the various parts of WiFi. I have in mind a simple setup
using WiFi as a bridge between two Ethernet-attached devices.

Cable modem---WRT54GL ~~~~~ WRT54GL---PC
[where '-' is Ethernet and '~' is WiFi]

Is this possible? If so what's the WiFi term for it and is it reasonably
straight-forward to configure? If not, what's a good Ethernet-attached
replacement device for the PC?

(There's also a chance that in the future I might attach another computer in
the next room about another 20' -- one more frame wall -- further from the
cable modem.)

[POSTED TO alt.internet.wireless - REPLY ON USENET PLEASE]

In <(E-Mail Removed)> on Wed, 22 Feb 2006 20:16:04 -0700, Jules
Dubois <(E-Mail Removed)> wrote:

>I want to get a Comcast cable internet connection and use WiFi to use the
>network in a computer room about 30 feet away. This doesn't seem to pose a
>big problem in theory, with one frame-and-drywall and one short adobe (~42
>inch-high mud brick) interior wall obstructing the line of sight between
>the cable connection and the PC. Because I have no Windows, just Linux, I
>would like to support Linksys' release of software in their WRT54GL
>"broadband router" and Windows-only software is useless to me.
>
>I understand the basics of IP networking but I'm having trouble
>understanding the various parts of WiFi. I have in mind a simple setup
>using WiFi as a bridge between two Ethernet-attached devices.
>
> Cable modem---WRT54GL ~~~~~ WRT54GL---PC
> [where '-' is Ethernet and '~' is WiFi]
>
>Is this possible? If so what's the WiFi term for it and is it reasonably
>straight-forward to configure? If not, what's a good Ethernet-attached
>replacement device for the PC?
>
>(There's also a chance that in the future I might attach another computer in
>the next room about another 20' -- one more frame wall -- further from the
>cable modem.)

Then you want the left WRT54GL configured as a wireless router, and wireless
network adapters (e.g., WMP54G, WPC54G, WUSB54G, WUSB54GC) for each computer.

--
Best regards, SEE THE FAQ FOR ALT.INTERNET.WIRELESS AT
John Navas <http://en.wikibooks.org/wiki/FAQ_for_alt.internet.wireless>

On Thursday 23 February 2006 08:16, John Navas <(E-Mail Removed)>
(<ulkLf.446443$(E-Mail Removed)>) wrote:

> [POSTED TO alt.internet.wireless - REPLY ON USENET PLEASE]
>
> In <(E-Mail Removed)> on Wed, 22 Feb 2006 20:16:04 -0700,
> Jules Dubois <(E-Mail Removed)> wrote:
>
>>[want wireless Internet for Linux; lack clues]
>>
>> Cable modem---WRT54GL ~~~~~ WRT54GL---PC
>> [where '-' is Ethernet and '~' is WiFi]
>>
>>Is this possible? If so what's the WiFi term for it and is it reasonably
>>straight-forward to configure? If not, what's a good Ethernet-attached
>>replacement device for the PC?
>
> Then you want the left WRT54GL configured as a wireless router, and
> wireless network adapters (e.g., WMP54G, WPC54G, WUSB54G, WUSB54GC) for
> each computer.

Linksys' current PCI adapters are reported to use Broadcom chips without
Linux support and USB adapters require additional Linux drivers for
networking over USB.

Does an "Ethernet bridge", such as Linksys' WET54G, fill the same role as
the products you listed above? I'm willing to go to some reasonable,
additional expense to avoid things like NDISWRAPPER, MadWiFi. and even
CDCEther.

I've spent well over forty hours over the last two weeks trying to
understand WiFi. I broke down today and bought a not-too-technical book to
help me understand. I believe now I could use two WRT54GLs to do what I
want, perhaps with third-party firmware, but that it's a project I should
put off until I have a working setup that I understand well.

Thanks for the follow-up, John.

Jules Dubois <(E-Mail Removed)> hath wroth:

>On Thursday 23 February 2006 08:16, John Navas <(E-Mail Removed)>
>(<ulkLf.446443$(E-Mail Removed)>) wrote:
>
>> [POSTED TO alt.internet.wireless - REPLY ON USENET PLEASE]
>>
>> In <(E-Mail Removed)> on Wed, 22 Feb 2006 20:16:04 -0700,
>> Jules Dubois <(E-Mail Removed)> wrote:
>>
>>>[want wireless Internet for Linux; lack clues]
>>>
>>> Cable modem---WRT54GL ~~~~~ WRT54GL---PC
>>> [where '-' is Ethernet and '~' is WiFi]
>>>
>>>Is this possible? If so what's the WiFi term for it and is it reasonably
>>>straight-forward to configure? If not, what's a good Ethernet-attached
>>>replacement device for the PC?

Yeah, that will work. The WRT54GL can run a variety of Linux based
replacement firmware. I like DD-WRT. That will take care of the
WRT54GL attached to the cable modem. So far, it's a fairly typical
installation.

However, you're apparently using the 2nd WRT54GL as a client adapter.
That will work because DD-WRT and other firmware support the client
mode. You can also setup the 2nd WRT54GL as a WDS bridge and get
exactly the same effect, with the added benifit of being able to
wirelessly connect to both routers.

However, this seems a bit overly complex for such a simple
installation. Just get a compatible 802.11g client radio for the PC
and be done with it. Lots of possible devices:
http://www.linux-wlan.org/docs/wlan_adapters.html.gz

>> Then you want the left WRT54GL configured as a wireless router, and
>> wireless network adapters (e.g., WMP54G, WPC54G, WUSB54G, WUSB54GC) for
>> each computer.

>Linksys' current PCI adapters are reported to use Broadcom chips without
>Linux support and USB adapters require additional Linux drivers for
>networking over USB.

There is no requirement that the client radios be from the same
manufacturer or use the same chipset. Incidentally, the WRT54GL has a
Broadcom chipset.

>Does an "Ethernet bridge", such as Linksys' WET54G, fill the same role as
>the products you listed above? I'm willing to go to some reasonable,
>additional expense to avoid things like NDISWRAPPER, MadWiFi. and even
>CDCEther.

Nothing wrong with NDISwrapper except that some cards report garbage
for signal strength and S/N ratio readings.

An ethernet bridge, as you describe it, will work as a client adapter.
What you have to watch out is how many MAC addresses the bridge will
pass. The WET54G will handle more than one (32 ?) so you can attach
more than one computer to it. However, there are quite a few similar
products (i.e. game adapters) that only do one. The data sheets are
useless for identifying this feature. I tried to make some sense of
the term "bridge" in the FAQ:
http://en.wikibooks.org/wiki/FAQ_for...ireless_Bridge

>I've spent well over forty hours over the last two weeks trying to
>understand WiFi. I broke down today and bought a not-too-technical book to
>help me understand.

You must be desperate. I never read the docs until after I've created
an insurmountable problem.

>I believe now I could use two WRT54GLs to do what I
>want, perhaps with third-party firmware, but that it's a project I should
>put off until I have a working setup that I understand well.
>
>Thanks for the follow-up, John.
--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[POSTED TO alt.internet.wireless - REPLY ON USENET PLEASE]

In <(E-Mail Removed)> on Fri, 24 Feb 2006 10:26:55
-0800, Jeff Liebermann <(E-Mail Removed)> wrote:

>[HUGE SNIP]

<SHAMELESS_PLUG>

I've come to really like the Apple Airport Express
<http://www.apple.com/airportexpress/> for this and many other applications.
It deserves to get much more attention. Well engineered, easy to setup and
use, universal power, small and compact (for on the go as well as at home),
both Windows and Mac, with Ethernet, USB, and audio ports, and with support
for WPA as well as WEP, it can act as wireless:

* Router
* Access point
* Ethernet client bridge
* Range extender
* Airtunes audio client for home theater system (driven by iTunes)
* Printer server (USB)

</SHAMELESS_PLUG>

--
Best regards, SEE THE FAQ FOR ALT.INTERNET.WIRELESS AT
John Navas <http://en.wikibooks.org/wiki/FAQ_for_alt.internet.wireless>

[POSTED TO alt.internet.wireless - REPLY ON USENET PLEASE]

<SHAMELESS_PLUG>

I've come to really like the Apple Airport Express
<http://www.apple.com/airportexpress/> for this and many other applications.
It deserves to get much more attention. Well engineered, easy to setup and
use, universal power, small and compact (for on the go as well as at home),
both Windows and Mac, with Ethernet, USB, and audio ports, and with support
for WPA as well as WEP, it can act as wireless:

* Router
* Access point
* Ethernet client bridge
* Range extender
* Airtunes audio client for home theater system (driven by iTunes)
* Printer server (USB)

</SHAMELESS_PLUG>

--
Best regards, SEE THE FAQ FOR ALT.INTERNET.WIRELESS AT
John Navas <http://en.wikibooks.org/wiki/FAQ_for_alt.internet.wireless>

John Navas <(E-Mail Removed)> wrote:
>I've come to really like the Apple Airport Express
><http://www.apple.com/airportexpress/>

I really like them too, though I still deploy Linksys W{RT,AP}54G
devices for most of my clients. The streaming audio feature can't be
beat!

A WWWeb GUI would be a nice addition, and they are fairly pricey, but
once set up and running I've never had a prolem with them!

On Friday 24 February 2006 11:26, Jeff Liebermann
<(E-Mail Removed)>
(<(E-Mail Removed)>) wrote:

>>> Jules Dubois <(E-Mail Removed)> hath wroth:
>>>
>>>>[want wireless Internet for Linux; lack clues]
>>>>
>>>> Cable modem---WRT54GL ~~~~~ WRT54GL---PC
>>>> [where '-' is Ethernet and '~' is WiFi]

> Yeah, that will work. The WRT54GL can run a variety of Linux based
> replacement firmware. I like DD-WRT.

After some additional research, I agree.

> However, you're apparently using the 2nd WRT54GL as a client adapter.

It seems this isn't the normal use for a WRT54G. I just like the idea
because the box runs Linux.

> That will work because DD-WRT and other firmware support the client
> mode.

Is "client mode" one of the key phrases I should be looking for?

> You can also setup the 2nd WRT54GL as a WDS bridge and get
> exactly the same effect, with the added benifit of being able to
> wirelessly connect to both routers.

Presumably you mean with another client adapter?

> However, this seems a bit overly complex for such a simple
> installation.

That's what they tell me at the stores where I've asked. The most
knowledgeable tech told me not try try it until I know more.

> Just get a compatible 802.11g client radio for the PC
> and be done with it. Lots of possible devices:
> http://www.linux-wlan.org/docs/wlan_adapters.html.gz

I'll look at these again. Do you have recommendation?

> Nothing wrong with NDISwrapper except that some cards report garbage
> for signal strength and S/N ratio readings.

I'd rather have something for which the manufacturer provides direct Linux
support or an Ethernet-attached device where support is more or less
universal. One of the other reasons I didn't want NDIS wrapper is my
assumption that it was not supported under AMD64 Linux; I find, however,
that it is already installed on my system with the stock Ubuntu kernel.

>
http://en.wikibooks.org/wiki/FAQ_for...ireless_Bridge

My newsreader breaks the quote above but Ilook at the page again in a few
minutes.

>>I've spent well over forty hours over the last two weeks trying to
>>understand WiFi. I broke down today and bought a not-too-technical book
>>to help me understand.
>
> You must be desperate.

I'd prefer it if you'd call me paranoid instead. I'd like things to work
the first time, but I feel I need to understand the details in case I have
to troubleshoot problems or call the cable company. I don't trust them.

(For example, I bought the cable modem this weekend but it reports that it
can't "acquire" a data-communication frequency on the cable line. The
first phone tech I talked to was a script monkey who asked me questions
like "What version of Windows do you have?", even after I explained the
symptoms in great detail. The second phone tech was a real tech who knew
better and ComCast is sending someone tomorrow.)

> I never read the docs until after I've created
> an insurmountable problem.

I swing both ways: plug it in to try it or RTFM until I've memorized it.

On Mon, 27 Feb 2006 20:22:13 -0700, Jules Dubois
<(E-Mail Removed)> wrote:

>> That will work because DD-WRT and other firmware support the client
>> mode.
>
>Is "client mode" one of the key phrases I should be looking for?

Yes. However, there are other terms that are used. "client bridge",
"wireless bridge", "CPE", and "client adapter" are some.

>> You can also setup the 2nd WRT54GL as a WDS bridge and get
>> exactly the same effect, with the added benifit of being able to
>> wirelessly connect to both routers.
>
>Presumably you mean with another client adapter?

No. WDS is quite different from an "ordinary" wireless client
adapter. It allows the "WDS bridge" box (2nd WRT54GL) to
simultaneously act as an access point and a wireless bridge. The
bridge part supplies the wireless connection to the main WRT54GL. The
access point part allows wireless connections by other wireless
clients such as laptops to the 2nd WRT54GL. You can also directly
connect an ethernet cable to the 2nd WRT54GL and the 2nd WRT54G will
act very much like a client adapter. Unlike some client adapters
(i.e. game adapters), you're not limited to connecting just one
computer to the 2nd WRT54GL.

>That's what they tell me at the stores where I've asked. The most
>knowledgeable tech told me not try try it until I know more.

I agree. Do some reading.

>I'll look at these again. Do you have recommendation?

No. I get into trouble making recommendations and then discovering
that there's some part of the puzzle that's incompatible or missing. I
also have limited experience with Linux devices. I'll pass.

>I'd rather have something for which the manufacturer provides direct Linux
>support or an Ethernet-attached device where support is more or less
>universal.

None of the manufacturers (that I know about) will directly support
Linux customers. If you call with a Linux question, they will usually
say that you should try it under Windoze to check the hardware, and
lots of luck with the Linux part. Besides, you get much better
support from the Linux user community than from the manufacturer.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 (E-Mail Removed)
# http://802.11junk.com (E-Mail Removed)
# http://www.LearnByDestroying.com AE6KS

On Tuesday 28 February 2006 14:24, Jeff Liebermann
<(E-Mail Removed)>
(<(E-Mail Removed)>) wrote:

> None of the manufacturers (that I know about) will directly support
> Linux customers. If you call with a Linux question, they will usually
> say that you should try it under Windoze to check the hardware, [...]

This is what I find with ComCast. Fortunately, I was able to translate
"ipconfig" talk into "dhclient" talk.

> Besides, you get much better support from the Linux user community than
> from the manufacturer.

I see. From your remark about dd-wrt, I find

Wireless Bridging is used to connect two LAN segments via a wireless
link. The two segments will be in the same subnet and looks like two
ethernet switches connected by a cable, to all computers on the
subnet. Since the computers are on the same subnet, broadcasts will
reach all machines allowing DHCP clients in one segment to get
their addresses from a DHCP server in a different segment.

http://wrt-wiki.bsr-clan.de/index.ph...ireless_Bridge

and a simple configuration guide at

http://wrt-wiki.bsr-clan.de/index.ph...Client_Bridged

Thanks to the "Linux community", and of course you and John, I find
something I can understand and which I think I can do. It also gives me
considerable leeway for any changes I might want to make in the future.