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B2 won't accept DHCP Offer in rescue mode

Got problems with your B2 or B3? Share and get helped!
HaydenMetz
Posts: 5
Joined: 09 Jul 2011, 22:32

B2 won't accept DHCP Offer in rescue mode

Post by HaydenMetz »

I changed the root password on my B2 to something too clever for me to remember, so I'm now trying to boot it using a USB stick so I can reset the root password. Unfortunately it's not working so far.

I know:
  • My B2 is booting off the USB disk and requesting an IP address from my router (I'm running wireshark on my network and I see the DHCP Discover from bubba); and
  • My router is replying with an address for the B2 (I can see the DHCP Offer in response to the discover), but
  • My B2 never actually takes the address (there is never a DHCP Request from the B2, and subsequent ARP requests for who owns the offered IP address don't ever get answered).
I've tried 2 different DHCP servers, both of which can serve up addresses to other clients, but bubba never completes the negotiation with either of them. Anyone seen behavior like this or have an explanation? And more importantly, does anyone know how to fix it?
ryz
Posts: 183
Joined: 12 Feb 2009, 06:03

Re: B2 won't accept DHCP Offer in rescue mode

Post by ryz »

Just a quick question you are using the WAN port of the Bubba when using the rescue usb?
HaydenMetz
Posts: 5
Joined: 09 Jul 2011, 22:32

Re: B2 won't accept DHCP Offer in rescue mode

Post by HaydenMetz »

Yup.
johannes
Posts: 1470
Joined: 31 Dec 2006, 07:12
Location: Sweden
Contact:

Re: B2 won't accept DHCP Offer in rescue mode

Post by johannes »

This behaviour is known when B2 (or B3 for that matter) doesn't have a disk connected, it then (supposedly) reboots after some time. But I suppose you have the disk connected?
/Johannes (Excito co-founder a long time ago, but now I'm just Johannes)
HaydenMetz
Posts: 5
Joined: 09 Jul 2011, 22:32

Re: B2 won't accept DHCP Offer in rescue mode

Post by HaydenMetz »

I do. The light on my USB stick comes on several seconds after the B2 boots and pretty much stays on. Also, my normal configuration is to use static IP addresses, so I don't think bubba would even start the DHCP negotiation unless it was booting off the USB device. I've tried this with two different USB thumb drives, the second of which I bought from excito (I had to change the line in the bubba.cfg to avoid doing a full install, but the thumb drive's file system is otherwise unaltered).

I maybe should add that my B2 doesn't perform the DHCP negotiation every time. Probably only half of the times I try booting into rescue mode off the USB drive do I see the DHCP Discover (or any network traffic for that matter). The other times the blue LED on the front keeps flashing but I never see any traffic on my wireshark capture. It (bubba) is not in my normal configuration, either, at least it never responds to pings on its configured static IP. I've left it in this state for maybe 15 minutes at most before power cycling and trying the rescue boot sequence again. I've assumed these failed boots are times when it didn't quite read the USB device correctly (although the access light exhibits the same behavior of coming on and staying on) based on comments I've read on the forum about flaky behavior booting off external USB devices, although there certainly could be something else going on there.
ryz
Posts: 183
Joined: 12 Feb 2009, 06:03

Re: B2 won't accept DHCP Offer in rescue mode

Post by ryz »

Have the WAN port worked before? That is did you use the WAN port in your setup?

It sound like either flaky hardware cable or that the two devices does not want to talk to each other. They might not agree on which link speed to use. You are sure you do not have an other device with the same MAC address on the lan?
johannes
Posts: 1470
Joined: 31 Dec 2006, 07:12
Location: Sweden
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Re: B2 won't accept DHCP Offer in rescue mode

Post by johannes »

Unfortunately, this behaviour is not unknown to us. On some of the B2 boards the USB boot is shaky. What you could try is:

- boot with usb as normal
- await the 4 Hz blink and USB activity (FS loading from USB)
- if the 4 Hz blink is cancelled within 2-3 seconds or the USB activity is not longer than 2-3 seconds, pull power and try again.

After a few attempts this usually runs through.

If you can't get it to work we'll natrually take it in for service or replace your board.
/Johannes (Excito co-founder a long time ago, but now I'm just Johannes)
HaydenMetz
Posts: 5
Joined: 09 Jul 2011, 22:32

Re: B2 won't accept DHCP Offer in rescue mode

Post by HaydenMetz »

Thanks for the info @johannes. I think when it doesn't work the blue LED keeps blinking at 4Hz and the USB stick LED stays lit too, but I'll have to pay more attention when I next get to try it (next week... I'm heading out of town for the weekend).

Something @ryz said also sparked an idea. I don't use the WAN port in my normal configuration, so I don't really know it works correctly. It _is_ able to start the DHCP negotiation, though, so it doesn't seem like it's a hardware failure or a cable problem. It occurred to me that I use 10.x.x.x for my local network (I can type the addresses faster), and bubba (like most devices) uses 192.168.x.x by default (I believe I read somewhere it uses 192.168.10.1 if it can't get an address through DHCP when it's operating normally). I've worked with devices before that couldn't actually handle any subnet besides their default, and it doesn't seem so crazy that the rescue boot mode might suffer from this weakness. I'll try putting my DHCP server in the 192.168.10.x subnet and have it serve addresses there as well and see if anything changes.
johannes
Posts: 1470
Joined: 31 Dec 2006, 07:12
Location: Sweden
Contact:

Re: B2 won't accept DHCP Offer in rescue mode

Post by johannes »

The last idea there about subnets might be worth to try yes, please let us know the outcome. THanks.
/Johannes (Excito co-founder a long time ago, but now I'm just Johannes)
MouettE
Site admin
Posts: 341
Joined: 06 Oct 2011, 19:45

Re: B2 won't accept DHCP Offer in rescue mode

Post by MouettE »

Hello,

I have the same issue with rescue mode, and just tried with a DHCP on a 192.168.1.x network, it doesn't work either.
johannes
Posts: 1470
Joined: 31 Dec 2006, 07:12
Location: Sweden
Contact:

Re: B2 won't accept DHCP Offer in rescue mode

Post by johannes »

Please give more details on what you do and where it fails. For instance, did you follow this guide?

http://wiki.excito.org/wiki/index.php/Rescue_System

Also, on B2 as stated earlier a few attempts might be required.
/Johannes (Excito co-founder a long time ago, but now I'm just Johannes)
nolla
Posts: 23
Joined: 11 Mar 2011, 13:16
Location: Turku, Finland

Re: B2 won't accept DHCP Offer in rescue mode

Post by nolla »

I guess that my bubba is going through the same issue: http://forum.excito.net/viewtopic.php?f=9&t=3400#p17329
MouettE
Site admin
Posts: 341
Joined: 06 Oct 2011, 19:45

Re: B2 won't accept DHCP Offer in rescue mode

Post by MouettE »

As soon as I get my serial access to work, I will investigate on this issue and post results.
HaydenMetz
Posts: 5
Joined: 09 Jul 2011, 22:32

Re: B2 won't accept DHCP Offer in rescue mode

Post by HaydenMetz »

Sorry I never got around to updating this thread. I tried booting using the rescue disk with my DHCP server in the 192.168.10.x subnet a few days after my last post, but I still had the same problem... my bubba would request a lease, but never actually take the address.

So I gave up on the rescue disk, popped the hard drive out and mounted it on another system, changed the root password to the same as my normal user account's password (copying the line in /etc/shadow from my user to root and updating appropriately), then rebooted bubba and did a passwd to set the root password to what I wanted. Since the whole reason I started down this path was to recover my root password that was enough for me.

For what it's worth @nolla, the problem I had doesn't seem to me to be the same as what you're experiencing with 2.4RC1. My bubba could start the DHCP negotation but not finish it, leaving it with no valid IP address and effectively dead to the outside world. That sounds different from your case (if I'm understanding and recalling it correctly) where bubba could take an address and talk through the WAN port correctly but not function properly on the LAN port. Although it may be related, because I tried tonight upgrading to 2.4RC1 myself and now I can't talk to my bubba no matter what I do. If I can't figure out what's going on I'll spawn off another thread for that issue, though.
Gordon
Posts: 1461
Joined: 10 Aug 2011, 03:18

Re: B2 won't accept DHCP Offer in rescue mode

Post by Gordon »

I'm thinking this may be related to an issue I had today when my cable modem dropped out (I'm actually receiving a public IP on the WAN interface through this).

It works after a full reset of all the networking components, but I found that the bubba firewall is missing a critical statement to be able to accept DHCP offerings. What I'm reading here seems to prove that by the time the box is ready to accept a different IP range than it requests by itself (which will the one used by the developer team) the firewall is up and blocking the incoming traffic on UDP 67-68.
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