DHCP not traversing DD-WRT v24 bridge with non-linux routers

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brainbone
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PostPosted: Thu Aug 07, 2008 17:10    Post subject: DHCP not traversing DD-WRT v24 bridge with non-linux routers Reply with quote
Problem:

It appears that when connecting a device running DD-WRT v24 configured as a bridge to a router that is not running linux, the DHCP server on the non-linux router is unable to service DHCP requests from clients connected to the dd-wrt v24 bridge.

Update: There are reports that the issue is resolved in SVN 11028, and presumably any builds newer than 11028. I have not had time to test this yet. See this thread for information on these newer builds.

Workarounds:

1) If you do not need repeater bridge mode and dd-wrt v23sp2 is available for your router, running dd-wrt v23sp2 in client bridge mode does work.

2) Using repeater or client mode (not repeater bridge, or client bridge) does work in v24, with the drawbacks of isolating the network segments behind NAT (complicating some configurations like access to shared LAN devices) and loosing the ability to roam the wireless network transparently.

3) Use static IP configuration on clients connected to the v24 bridge.

Problem router list:

Here are lists I've compiled so far of compatible / incompatible routers. These lists are by no means complete, so please add to them.

Note that any of the routers listed here running stock firmware that do not work with a dd-wrt v24 bridge, do work with a dd-wrt v24 bridge if you are able to flash them to dd-wrt firmware, or any other linux based firmware.

Incompatible Routers, running stock firmware, that have been reported to not service DHCP requests to clients connected via a dd-wrt v24 bridge.

Code:
1) Actiontec:

  a) MI424-MR (OS: Unknown; Chipset: Unknown)

2) Dynex:

  a) WEGRTR (OS: Vxworks; Chipset: Broadcom)

  b) WGRTR (OS: Vxworks; Chipset: Broadcom)

3) Linksys:

  a) WRT54G v5, v6, v8 (OS: VXworks; Chipset: Broadcom)

  b) WRT54GC-EU (OS: VXworks; Chipset: Marvell)
 
  c) WRT54G v7 (OS: VXworks; Chipset: Atheros)

  d) WRT54GS v5, v7 (OS: VXworks; Chipset: Broadcom)

  e) WRK54G V3 (OS: VXworks; Chipset: Atheros)


4) Motorola:

  a) SBG900 (OS: Unknown; Chipset: Unknown)

5) Netgear:

  a) MR814 v3 (OS: Unknown; Chipset: Unknown)

  b) WGT624 v1, v2, v3 (OS: Vxworks; Chipset Atheros)

  c) WGR614 v5 (OS: Vxworks; Chipset Broadcom)

6) Sweex

  a) LW050v2 (OS: VxWorks?; Chipset; Atheros)



Compatible Routers, running stock firmware, that do service DHCP requests to clients connected via a dd-wrt v24 bridge.

Code:

1) Buffalo:

  a) WHR-HP-G54 (OS: Linux; Chipset: Broadcom)

2) Cisco:

  a) Aironet 1130AG (OS: Unknown; Chipset: Unknown)

3) Linksys:

  a) WRT54G v3, v3.1, V4 (OS: Linux; Chipset: Broadcom)

  b) WRT54GL v1, v1.1 (OS: Linux; Chipset: Broadcom)

  c) WRT54GS v4 (OS: Linux; Chipset: Broadcom)

  d) WRT54GX2 (OS: Linux; Chipset: Realtek)

  e) WRT300N v1 (OS: Linux; Chipset Broadcom)
 
  f) WRT350N v1 (OS: Linux; Chipset Broadcom)

4) ZyXEL:

  a) P330W (OS: Linux; Chipset: Realtek)


Last edited by brainbone on Fri Dec 05, 2008 13:58; edited 16 times in total
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redhawk0
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PostPosted: Thu Aug 07, 2008 17:41    Post subject: Reply with quote
http://www.dd-wrt.com/wiki/index.php/Repeater_Bridge

and

http://www.dd-wrt.com/wiki/index.php/Client_Bridged

Have been updated in the wiki tutorials under Linking Routers . A link to this thread is included and all problem routers should be posted here.

We should get a pretty comprehensive list of problematic non-linux units this way.

Thanx for all your constructive ideas and assistance, Brainbone.

redhawk

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brainbone
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PostPosted: Thu Aug 07, 2008 20:32    Post subject: Reply with quote
Thank you redhawk0.

With more feedback, hopefully the problem(s) causing this issue can be isolated and solved.

One other thing I'd be interested in hearing of is atheros devices running DD-WRT v24 bridging to both linux and non-linux routers, and the status of DHCP in both situations. So far, it seems most the reports are of broadcom based bridges running v24 connecting to various routers (atheros, realtek, broadcom).


Last edited by brainbone on Fri Aug 08, 2008 1:01; edited 1 time in total
paolorenzo
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PostPosted: Fri Aug 08, 2008 0:53    Post subject: Reply with quote
Thanks for this brainbone. I hope this thread would be drama-free. Laughing

May I suggest that this be converted to a sticky thread? At least until the root cause has been identified?
brainbone
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PostPosted: Fri Aug 08, 2008 19:25    Post subject: Reply with quote
[EDIT]
After a second look, and confirmed by redhawk0, this configuration is really nothing more than a long way around to a non bridged repeater (with the added benefits of AutoAP), so unfortunately nothing gained here over what's already in workaround #2 in the first post. Sorry for the false alarm.
[/EDIT]

Those having this DHCP issue may want to take a look over this quote from Dan, copied from "that other thread".

I haven't had a chance to try this yet, but wanted to post this here to get some feedback on other primary routers this potential workaround may work with.

Dan wrote:
I had been unable to obtain DHCP from a Speedtouch device when passing through a Client Bridge or Repeater using DDWRT. I had solved it using fixed IPs on each client.

However, by eventually getting round to
trying for a 2nd time, now that there is an easy method of implementing the package, in just one firmware upgrade
Quote:
How to scan for ANY OPEN WIFI? SOLVED!!!

I have a solution so that I do not need to do anything to Client PCs connecting to the Repeater.

Using a WRT54GL v1.1 and now a whr-hp-g54

(1)I loaded, as recommended by Kuthulu

http://kuthulu.no-ip.org/dd-wrt.v24_micro_generic.aapng.20070822RC1b.bin

(2) Setup Router IP and DHCP at an out of the way address 192.168.15.1 with DHCP starting at 100

(3)Set up a virtual SSID with simple WEP encryption

(4)Went to the location

http://my_router_ip/user/cgi-bin/autoap.cgi in my case it is http://192.168.15.1/user/cgi-bin/autoap.cgi

Started AutoAP and setup my preferred Ssids for AutoAP to make use of. Waited a few minutes.

(5) The PC attached to the Repeater Router received an IP within the correct range and Internet connection worked.

(6) Provided, I remember to tick the bridge connection on the VSsid the wireless clients obtain DHCP.

When I look inside the AutoAp repeater router, as expected since it works, I can see the address supplied to it from the SpeedTouch.

A solution/ work around seems have been available already. DD-WRT v24 RC-1 (08/22/07).
Almost 12 months!

Perhaps this also narrows the focus as well?


Last edited by brainbone on Fri Aug 08, 2008 21:50; edited 5 times in total
redhawk0
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PostPosted: Fri Aug 08, 2008 19:31    Post subject: Reply with quote
brainbone wrote:
Those having this DHCP issue may want to take a look over this quote from Dan, copied from "that other thread".

I haven't had a chance to try this yet, but wanted to post this here to get some feedback on other primary routers this potential workaround may work with.

Dan wrote:
I had been unable to obtain DHCP from a Speedtouch device when passing through a Client Bridge or Repeater using DDWRT. I had solved it using fixed IPs on each client.

However, by eventually getting round to
trying for a 2nd time, now that there is an easy method of implementing the package, in just one firmware upgrade
Quote:
How to scan for ANY OPEN WIFI? SOLVED!!!

I have a solution so that I do not need to do anything to Client PCs connecting to the Repeater.

Using a WRT54GL v1.1 and now a whr-hp-g54

(1)I loaded, as recommended by Kuthulu

http://kuthulu.no-ip.org/dd-wrt.v24_micro_generic.aapng.20070822RC1b.bin

(2) Setup Router IP and DHCP at an out of the way address 192.168.15.1 with DHCP starting at 100

(3)Set up a virtual SSID with simple WEP encryption

(4)Went to the location

http://my_router_ip/user/cgi-bin/autoap.cgi in my case it is http://192.168.15.1/user/cgi-bin/autoap.cgi

Started AutoAP and setup my preferred Ssids for AutoAP to make use of. Waited a few minutes.

(5) The PC attached to the Repeater Router received an IP within the correct range and Internet connection worked.

(6) Provided, I remember to tick the bridge connection on the VSsid the wireless clients obtain DHCP.

When I look inside the AutoAp repeater router, as expected since it works, I can see the address supplied to it from the SpeedTouch.

A solution/ work around seems have been available already. DD-WRT v24 RC-1 (08/22/07).
Almost 12 months!

Perhaps this also narrows the focus as well?


Yes...but Dan is talking about Repeater mode...not Repeater Bridge mode. A router in Repeater mode is it's own DHCP server. It will hand out a DHCP address independant of the Host AP. (different subnet 192.168.X.1 in this case 15.1)

I thought the only DHCP pass-through issue was with Client Bridge and Repeater Bridge where the connecting client needs to obtain an IP address from the Host AP?

Please correct me if my thinking is incorrect here.

redhawk

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brainbone
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PostPosted: Fri Aug 08, 2008 19:35    Post subject: Reply with quote
redhawk0 wrote:

Yes...but Dan is talking about Repeater mode...not Repeater Bridge mode

[...]

Please correct me if my thinking is incorrect here.

redhawk


First time I read this, that's what I was thinking, but, Dan says "The PC attached to the Repeater Router received an IP within the correct range and Internet connection worked." and " I can see the address supplied to it from the SpeedTouch.". While it is a bit ambiguous in context, it sounds like somehow the Speedtouch is able to get it's DHCP through to clients on the bridge... unless I'm reading too much into it.
redhawk0
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PostPosted: Fri Aug 08, 2008 19:46    Post subject: Reply with quote
brainbone wrote:
redhawk0 wrote:

Yes...but Dan is talking about Repeater mode...not Repeater Bridge mode

[...]

Please correct me if my thinking is incorrect here.

redhawk


First time I read this, that's what I was thinking, but, Dan says "The PC attached to the Repeater Router received an IP within the correct range and Internet connection worked." and " I can see the address supplied to it from the SpeedTouch.". While it is a bit ambiguous in context, it sounds like somehow the Speedtouch is able to get it's DHCP through to clients on the bridge... unless I'm reading too much into it.


I think he was refering to the Speedtouch issued IP address to his unit...not DHCP passthrough. They are 2 different things...The IP supplied to his unit will be in the same Subnet....the DHCP issued by the Repeater (unbridged) will be a different subnet. Autoap.cgi only works on Repeater mode...not Repeater Bridge mode.

redhawk

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brainbone
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PostPosted: Fri Aug 08, 2008 20:40    Post subject: Reply with quote
redhawk0 wrote:

I think he was refering to the Speedtouch issued IP address to his unit...not DHCP passthrough.


Yes. This would make more sense with the AutoAP configuration, and really gains you nothing over a non bridged repeater or client.
redhawk0
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PostPosted: Fri Aug 08, 2008 20:47    Post subject: Reply with quote
brainbone wrote:
redhawk0 wrote:

I think he was refering to the Speedtouch issued IP address to his unit...not DHCP passthrough.


Yes. This would make more sense with the AutoAP configuration, and really gains you nothing over a non bridged repeater or client.


It really depends on your application. I use WLAN Repeater mode a LOT. I spend many of my days in hotel rooms....some of which have very poor signal from the hotel router to my laptop....however, from router to router the signal is pretty good...then I can connect to my own router in my own subnet and not worry about others being able to "break in" to my private subnet....or I can share the wireless connection (SSID,encryption) with co-workers and we can still share information on the private subnet.

So...for quality of signal, and security reasons the WLAN Repeater has it beat hands down. The Repeater Bridge is just that...used for bridging units. I use a Client Bridge (essentially the same thing...except for wireless...and I did have it setup as an RB at one time) for my network printer at the house. I can, from ANY of my Bridged units print to this one printer.

redhawk

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brainbone
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PostPosted: Fri Aug 08, 2008 21:09    Post subject: Reply with quote
redhawk0 wrote:
It really depends on your application.


My apologies for not being clear. I didn't mean "gains you nothing" as a slight against AutoAP or non-bridged repeaters, just that a non-bridged repeater is no real gain in the context of trying to isolate this DHCP/bridging issue.

But yes, non-bridged repeaters (and AutoAP) are quite useful -- use them often myself.
redhawk0
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PostPosted: Fri Aug 08, 2008 21:13    Post subject: Reply with quote
brainbone wrote:
redhawk0 wrote:
It really depends on your application.


My apologies for not being clear. I didn't mean "gains you nothing" as a slight against AutoAP or non-bridged repeaters, just that a non-bridged repeater is no real gain in the context of trying to isolate this DHCP/bridging issue.

But yes, non-bridged repeaters (and AutoAP) are quite useful -- use them often myself.


Understood now...thanx...all information is good though...but sometimes the wrong info can cloud the real underlying issue. I hope we can come to a resolution some day with this DHCP pass-through.

At least we know the source now....it doesn't help much for those that have non-linux units for a host...but at least the issue is now documented.

redhawk

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Dan
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PostPosted: Sat Aug 09, 2008 1:43    Post subject: Reply with quote
Congratulations to redhawk0 on his analysis, of my less than adequate contribution, of what I only see is a tempory solution for those who have changes in client PCs and thus would have to implement manually IPs and DNS on each.

Quote:
I have a solution so that I do not need to do anything to Client PCs connecting to the Repeater.


This was the impetus for my contribution.

I have an imperfect understanding of what is fully taking place and the differences in Repeater and Repeater bridge modes so I looked only for a way through to a simpler solution.

Remember, I had to tick the Bridge Option for the wireless clients to receive DHCP from the Repeater's subnet range.

Is the process available without using AutoAp?
(I will try and test when I get chance)

And, yes the problem awaiting solution in the longer term is DHCP passthrough in certain situations.

Keep up the good work brainbone and redhawk0.

P.S. I have altered my post in the other thread to remove as much ambiguity as possible, as regards where DHCP is coming from.


Last edited by Dan on Sat Aug 09, 2008 8:49; edited 1 time in total
switch
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PostPosted: Sat Aug 09, 2008 8:47    Post subject: Reply with quote
Add to that list literally ANY Cisco device.
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redhawk0
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PostPosted: Sat Aug 09, 2008 11:59    Post subject: Reply with quote
Dan wrote:

Is the process available without using AutoAp?
(I will try and test when I get chance)


Yes...You can basically just remove the autoap.cgi from the repeater. But you manually have to type in the "Physical" SSID of the unit you want to repeater on the wireless>>basic tab.

The instructions are outlined in WLAN_Repeater.
http://www.dd-wrt.com/wiki/index.php/Linking_Routers

This is the setup that I use all the time. (memorized a long time ago now)

redhawk

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