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#306032 - 12/01/2008 06:54 Re: Wireless bridging! [Re: Shonky]
Shonky
pooh-bah

Registered: 12/01/2002
Posts: 2009
Loc: Brisbane, Australia
And v23 SP2 doesn't seem to support AES-CCMP that I can see.
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Christian
#40104192 120Gb (no longer in my E36 M3, won't fit the E46 M3)

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#306035 - 12/01/2008 11:40 Re: Wireless bridging! [Re: Shonky]
Dignan
carpal tunnel

Registered: 08/03/2000
Posts: 12338
Loc: Sterling, VA
Weird, I thought I'd gotten sp2. I might try that release candidate later today.

Are you bridging with an Airport, though?
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Matt

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#306036 - 12/01/2008 11:44 Re: Wireless bridging! [Re: Dignan]
Shonky
pooh-bah

Registered: 12/01/2002
Posts: 2009
Loc: Brisbane, Australia
No. Mine are both WRT54Gs. Technically you're not bridging with an Airport either. In your case the Airport is just working as a normal access point.
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Christian
#40104192 120Gb (no longer in my E36 M3, won't fit the E46 M3)

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#306039 - 12/01/2008 13:55 Re: Wireless bridging! [Re: Dignan]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14491
Loc: Canada
Originally Posted By: Dignan
Weird, I thought I'd gotten sp2. I might try that release candidate later today.

Are you bridging with an Airport, though?


Make sure you get exactly the same version I used here, as we know that one works.

And we're not really "bridging" -- the linksys is just being an ordinary wireless client here, and it should work with any other router in that mode.

Cheers

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#306041 - 12/01/2008 14:21 Re: Wireless bridging! [Re: Shonky]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
Well, I didn't include details, but they're relevant to explain why that doesn't disprove how I understand it to work.

Clients behind an 802.11 bridge are all seen with the same MAC address on the far side, the MAC of the bridge itself. You can get one DHCP address, but since DHCP uses the MAC address as the identifier, you can't have more than one device get a DHCP address, including the bridge itself.

Your situation has exactly one DHCP-acquired address at or behind the bridge.
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Bitt Faulk

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#306042 - 12/01/2008 14:31 Re: Wireless bridging! [Re: mlord]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
I think that part of the problem is that you, Mark, are setting up a router, while Dignan is trying to set up a bridge. I get the impression that you have put the "external" IP address of the DD-WRT system in your normal network, but the clients behind it are in a different network. In general, it's possible to make this work, but it's more complicated. Can you make a connection to those clients from your normal network? My gut tells me no.
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Bitt Faulk

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#306043 - 12/01/2008 14:41 Re: Wireless bridging! [Re: mlord]
Dignan
carpal tunnel

Registered: 08/03/2000
Posts: 12338
Loc: Sterling, VA
Well, I got the release candidate, and now everything appears to be working! I guess they didn't have the encryption stuff really worked out correctly in the older releases. I'll have to keep up with the firmware (though I'll probably take the "if it aint broke, don't fix it" approach).

In the end, I still wasn't able to use WPA Personal on the Linksys, even though the Airport was in WPA/WPA2 Personal mode. But the Linksys now has completely different encryption options, including WPA2 Personal (it wasn't there before). That one worked.

Thanks for all your help, everyone. I appreciate the assistance greatly.
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Matt

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#306044 - 12/01/2008 14:51 Re: Wireless bridging! [Re: wfaulk]
Dignan
carpal tunnel

Registered: 08/03/2000
Posts: 12338
Loc: Sterling, VA
Originally Posted By: wfaulk
Clients behind an 802.11 bridge are all seen with the same MAC address on the far side, the MAC of the bridge itself. You can get one DHCP address, but since DHCP uses the MAC address as the identifier, you can't have more than one device get a DHCP address, including the bridge itself.

Sadly, I was reading the DD-WRT forums last night, and it appears that this is true. There is only one MAC for anything at the bridge and beyond.

The weird thing is that some users have reported being able to plug multiple devices into the WRT54G in bridge mode, while others were only able to plug in one (which is technically how it should work, I guess). I'll know either way in a few minutes, when I plug in my devices downstairs. I'll let you know.

*edit*
Well, it doesn't appear to be working in my setup. The wireless transmission speed isn't very good either.


Edited by Dignan (12/01/2008 15:16)
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#306045 - 12/01/2008 15:02 Re: Wireless bridging! [Re: wfaulk]
peter
carpal tunnel

Registered: 13/07/2000
Posts: 4180
Loc: Cambridge, England
Originally Posted By: wfaulk

Clients behind an 802.11 bridge are all seen with the same MAC address on the far side, the MAC of the bridge itself. You can get one DHCP address, but since DHCP uses the MAC address as the identifier, you can't have more than one device get a DHCP address, including the bridge itself.

RFC2131 says a DHCP server "MUST" deal with clients that send a "client identifier", and key off that rather than the MAC address; I don't know whether any common DHCP clients do send their MAC address as a client identifier, but if they do, several of them could DHCP through the same bridge.

Peter

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#306048 - 12/01/2008 15:45 Re: Wireless bridging! [Re: peter]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
I don't believe I have ever seen a DHCP client that supported that option. But your point remains that it could work. In fact, the bridge could do some packet modification to DHCP packets to help its clients use it transparently. I don't think we'll see that happen, though. It would have been nice if the 802.11 folks could have provided the ability to have multiple MAC addresses going over a single connection.
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Bitt Faulk

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#306049 - 12/01/2008 16:16 Re: Wireless bridging! [Re: wfaulk]
peter
carpal tunnel

Registered: 13/07/2000
Posts: 4180
Loc: Cambridge, England
Originally Posted By: wfaulk
I don't believe I have ever seen a DHCP client that supported that option. But your point remains that it could work. In fact, the bridge could do some packet modification to DHCP packets to help its clients use it transparently. I don't think we'll see that happen, though.

In theory, it wouldn't have to modify the packets. If it was a "true bridge" and not just an AP/client relationship, the APs could figure out which MAC addresses live on which side of the bridge, and tunnel whole Ethernet frames across the wireless -- for complete transparency even to "dumb" DHCP clients and servers. Again, I've no idea whether this actually happens in practice, but OTOH presumably there's some difference between AP/client and bridge modes, as all those screenshots have them listed separately...?

Peter

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#306056 - 12/01/2008 20:18 Re: Wireless bridging! [Re: wfaulk]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14491
Loc: Canada
The DD-WRT firmware claims to implement "DHCP relay" for purposes like this. Dunno much else about it, though.

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#306057 - 12/01/2008 20:21 Re: Wireless bridging! [Re: Dignan]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14491
Loc: Canada
Originally Posted By: Dignan
Originally Posted By: wfaulk
Clients behind an 802.11 bridge are all seen with the same MAC address on the far side, the MAC of the bridge itself. You can get one DHCP address, but since DHCP uses the MAC address as the identifier, you can't have more than one device get a DHCP address, including the bridge itself.

Sadly, I was reading the DD-WRT forums last night, and it appears that this is true. There is only one MAC for anything at the bridge and beyond.

The weird thing is that some users have reported being able to plug multiple devices into the WRT54G in bridge mode, while others were only able to plug in one (which is technically how it should work, I guess). I'll know either way in a few minutes, when I plug in my devices downstairs. I'll let you know.

*edit*
Well, it doesn't appear to be working in my setup. The wireless transmission speed isn't very good either.


Mmm... "client bridge" should be better performance than "repeater bridge". But "repeater bridge" should support multiple MACs without issue.

One thing that might be possible/acceptable, would be to have the DD-WRT run DHCP+NAT for it's local clients, so only one MAC is needed across the wireless bridge. EDIT: that's what "client" mode (no "bridge") does on the DD-WRT. EDIT-2: but not necessary.. see next post.

I may dig mine out again and play some more here now..


Edited by mlord (12/01/2008 21:17)

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#306058 - 12/01/2008 20:22 Re: Wireless bridging! [Re: wfaulk]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14491
Loc: Canada
Originally Posted By: wfaulk
I think that part of the problem is that you, Mark, are setting up a router, while Dignan is trying to set up a bridge. I get the impression that you have put the "external" IP address of the DD-WRT system in your normal network, but the clients behind it are in a different network.


No, I had everything (both APs etc..) all together on a single bridged subnet.

Cheers

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#306060 - 12/01/2008 20:40 Re: Wireless bridging! [Re: mlord]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14491
Loc: Canada
Okay, still no problems here.

I have my DD-WRT (Linksys WRT54GS_v2) configured as "client bridge" over the wireless, and I now have two wired PCs plugged into it using remote DHCP, and now surfing the internet.

The DD-WRT is relaying everything over WiFi (WPA2-Personal/PSK) to another brand of WiFi access point (AP) in another part of the house, and that AP is wired to the internal LAN here.

A wired server on the internal LAN provides DHCP service for all, and is also the internet gateway for our external DSL connection.

File transfer throughput (NVSv3) to/from a DD-WRT attached PC, to the wired server at the far end, is about 20 mbits/second, which is pretty much what one should expect over a Wireless-G connection (under 50% of the raw 54mbits/sec rate).

Any questions?

Cheers


Edited by mlord (12/01/2008 21:09)

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#306061 - 12/01/2008 20:54 Re: Wireless bridging! [Re: mlord]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14491
Loc: Canada
And just for a proper demo, I now have one of the two remote PC's connected across the bridge to an Empeg with EmpegWebLite running, with the active visuals display and all working.. while at the same time I'm using the other machine to surf, email, and write this posting.

Cheers


Attachments
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#306063 - 12/01/2008 21:04 Re: Wireless bridging! [Re: wfaulk]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14491
Loc: Canada
Originally Posted By: wfaulk
I don't believe I have ever seen a DHCP client that supported that option. But your point remains that it could work. In fact, the bridge could do some packet modification to DHCP packets to help its clients use it transparently. I don't think we'll see that happen, though. It would have been nice if the 802.11 folks could have provided the ability to have multiple MAC addresses going over a single connection.


Here's the log from the DHCP server across the wireless bridge from the two PCs that are using it for their config:
Code:
dhcpd: DHCPDISCOVER from 00:18:8b:a7:bf:42 via 10.0.0.144
dhcpd: DHCPOFFER on 10.0.0.6 to 00:18:8b:a7:bf:42 via 10.0.0.144
dhcpd: DHCPREQUEST for 10.0.0.6 (10.0.0.2) from 00:18:8b:a7:bf:42 via 10.0.0.144
dhcpd: DHCPACK on 10.0.0.6 to 00:18:8b:a7:bf:42 via 10.0.0.144
dhcpd: DHCPDISCOVER from 00:13:72:6a:8f:5c via 10.0.0.144
dhcpd: DHCPOFFER on 10.0.0.4 to 00:13:72:6a:8f:5c via 10.0.0.144
dhcpd: DHCPREQUEST for 10.0.0.4 (10.0.0.2) from 00:13:72:6a:8f:5c via 10.0.0.144
dhcpd: DHCPACK on 10.0.0.4 to 00:13:72:6a:8f:5c via 10.0.0.144


10.0.0.2 is the wired DHCP server on the far side from the DD-WRT,
10.0.0.[46] are the bridged clients plugged into the DD-WRT, and
10.0.0.144 is the DD-WRT bridge itself, performing the DHCP-relays.

Very slick!


Edited by mlord (12/01/2008 21:10)

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#306064 - 12/01/2008 21:14 Re: Wireless bridging! [Re: Dignan]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14491
Loc: Canada
Originally Posted By: Dignan

The weird thing is that some users have reported being able to plug multiple devices into the WRT54G in bridge mode, while others were only able to plug in one (which is technically how it should work, I guess). I'll know either way in a few minutes, when I plug in my devices downstairs. I'll let you know.

*edit*
Well, it doesn't appear to be working in my setup. The wireless transmission speed isn't very good either.


If you are *sure* that it is not working, then that would be the fault of the DHCP server in the airport, not handling the DHCP-relay requests from the DD-WRT.

But you can still use things, if you don't mind having the DD-WRT perform NAT for you. That's the wireless "client" mode of DD-WRT. You'll also then have to enable NAT and DHCP-server on the DD-WRT, but it should all work fine. The airport will see only a single MAC (from DD-WRT), and everyone will still see the internet just fine.

Clients behind DD-WRT will be able to establish connections to clients on the rest of your LAN, but the reverse will not be true -- unless you also set up port forwarding etc.. on the DD-WRT.

EDIT: or perhaps it could all work fine the way you had it, if you just enable DHCP service on DD-WRT. Not sure if it allows that in "client bridge" mode, though.

Cheers


Edited by mlord (12/01/2008 21:16)

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#306065 - 12/01/2008 22:57 Re: Wireless bridging! [Re: wfaulk]
Shonky
pooh-bah

Registered: 12/01/2002
Posts: 2009
Loc: Brisbane, Australia
Yeah well I'm not sure how the DHCP stuff works exactly, but it definitely does and with more than one client. I also plug my empeg into the client bridge to put it on the network and occasionally my laptop (to get a hard wired 100Mbit connection to my PVR via the WRT54G's built in switch).

I rely on the MAC address passing through since I have some fixed DHCP assignments.

My entire home network is a single 192.168.1.x subnet.
_________________________
Christian
#40104192 120Gb (no longer in my E36 M3, won't fit the E46 M3)

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