No Internet: DHCP works, but no IP.

MTsoul · 2009-08-29 19:41:45

I don't know what exactly caused it, but this was within the recent few weeks.

Symptom: No IP address, even though DHCP (dhclient and dhcpcd) works perfectly. After invoking dhcpcd and obtaining an IP, ifconfig still shows nothing.

I don't know if it matters, but I have two NICs, and it doesn't matter which one I connect to, it's the same thing.

I can confirm that this is not my network's problem, since the same machine with a dual-booted Windows works.

I can also confirm that this is definitely a recent upgrade, not some mis-config issue (unless a default config is causing this). I thought I borked my machine completely, so I reinstalled Arch entirely. Network is fine, until I did a full system upgrade. Then the same thing happened again.

This is so weird. I'd appreciate any help!

syväpaahto · 2009-08-29 20:20:29

can you give more info on what type of adapter you are using? What are the outputs of lsusb and lspci. Output of dmesg would be nice too.

MTsoul · 2009-08-29 20:55:20

lsusb returns nothing but my keyboard/mouse

lspci | grep net
00:19.0 Ethernet controller: Intel Corporation 82566DC-2 Gigabit Network Connection (rev 02) # on-board NIC
07:01.0 Ethernet controller: 3Com Corporation 3c905B 100BaseTX [Cyclone] (rev 30) # pci NIC

I even took out the PCI card, rebooted, same thing.

And since I have no internet on the broken computer, I'll just type out what's relevant here. Let me know if you want more.

eth1 is on-board intel card, and eth0 is the PCI card.

dmesg | grep eth

eth1: (PCI Express: 2.5GB/s:Width x1) <mac here>
eth1: Intel(R) Pro/2000 Network Connection
eth1: MAAC: 7, PHY:6, PBA No: ffffff-0ff

eth0: setting half-duplex.

eth1 NIC link is Up 10 mbps half duplex, flow control : none
eth1: autonegotiated half duplex but link partner cannot autoneg. Try forcingfull duplex if link gets many collisions.
eth1: 110/100 speed: disabling TSO
eth1: changing MTU from 1500 to 576
eth1: changing MTU from 576 to 1500

<repeat the above 5 lines 7 times>

That's about it. Any ideas what might be wrong? Thanks.

R00KIE · 2009-08-29 21:48:57

Where are you trying to connect your pc? It seems that if it is autonegotiating to 10 mbps half duplex then something may be wrong on the other end, try with another cable (shorter if yours is long and one that is known to be working).
The MTU changing can be dealt with later I believe, first try to solve that autonegotiation problem.

MTsoul · 2009-08-30 01:36:46

PC -> Hub -> Modem.

It's not anything beyond the PC. This PC used to be elsewhere, and in its place I had the Arch computer that's working right now. I put this PC in its place and it's no longer working. Absolutely no reason How can dhcp possibly work without affecting ifconfig?

Arch Linux

#1 2009-08-29 19:41:45

No Internet: DHCP works, but no IP.

#2 2009-08-29 20:20:29

Re: No Internet: DHCP works, but no IP.

#3 2009-08-29 20:55:20

Re: No Internet: DHCP works, but no IP.

#4 2009-08-29 21:48:57

Re: No Internet: DHCP works, but no IP.

#5 2009-08-30 01:36:46

Re: No Internet: DHCP works, but no IP.

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