[SOLVED] dhcpcd ignores dhcp offers

d0wn_under · Last edited by d0wn_under on Sun Apr 01, 2007 12:45 pm; edited 1 time in total

I've just moved to cable modem from dialup adsl and linux can't get an IP from the network. Windows works fine, it sends out the dhcp requests, gets the offers back and assigns itself an ip. Linux sends out the requests, gets loads of offers back (watching with wireshark) but just ignores them.

I've tried starting dhcpcd with -d to get some debug but all I see is the MAC address it is using.

ifconfig after a dhcpcd attempt shows RX packets 7405, TX packets 22 so stuff is moving, no errors or dropped packets. I've also tried starting with -r to see if that helps, it didn't.

dhcpcd works fine getting an ip from my internal network.

Anyone any idea of how to fix it or what to look for next?
_________________
This sig left intentionally blank.

UberLord · Posted: Sat Mar 31, 2007 5:58 pm Post subject:

What version of dhcpcd? If dhcpcd-2.x, try dhcpcd-3.x
_________________
Use dhcpcd for all your automated network configuration needs
Use dhcpcd-ui (GTK+/Qt) as your System Tray Network tool

beatryder · Veteran Joined: 08 Apr 2005 Posts: 1138

d0wn_under · Posted: Sun Apr 01, 2007 8:07 am Post subject:

I haven't had that much logging but I agree that it looks similar. I've just tried the latest knoppix and that has the same results.

I'm about to try freebsd, see if it is something in the linux implementation of the dhcp client.
_________________
This sig left intentionally blank.

UberLord · Posted: Sun Apr 01, 2007 10:02 am Post subject:

Those logs show that dhcpcd is working fine, just the DHCP server is a little slow.

FreeBSD (vanilla) uses dhclient, which is not the same same dhcpcd AT ALL. Would be better to use the same dhcp client on both platforms

Luckily, dhcpcd works on FreeBSD a well. Very easily using Gentoo/FreeBSD as our scripts support it. On vanilla FreeBSD you'll have to start/stop dhcpcd by hand.
_________________
Use dhcpcd for all your automated network configuration needs
Use dhcpcd-ui (GTK+/Qt) as your System Tray Network tool

d0wn_under · Posted: Sun Apr 01, 2007 12:44 pm Post subject: Solved

It appears that it is to do with MAC addresses.

I tried booting the windows laptop into linux and it got an IP so I tried the normal desktop (the one I had problems with) with the MAC address from the laptop. It worked!

Looks like the cable company has locked onto the first MAC address saw.

I'm not sure now whether to try to stay off line till the lease expires and then try with a different MAC to see if that one works or whether just to start changing MACs. I'd rather not change them as that would give me to NICs with the same MAC although they would be on different networks so I could get away with it.
_________________
This sig left intentionally blank.