Short version: dhclient works on wireless but not on wired ethernet
I am on Ubuntu 18.04 LTS.
This is almost exactly the same as this: Cannot receive DHCP OFFER on ethernet
I can get a DHCP based address via Wifi, not via the wired NIC. That goes for both the internal NIC and the integrated NIC. Both do work on Windows, so I am assuming it to be an Ubuntu problem.
This is the output of dhclient;
dhclient enp3s0 -d
Internet Systems Consortium DHCP Client 4.3.5
Copyright 2004-2016 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Listening on LPF/enp3s0/c0:3f:d5:65:1a:22
Sending on LPF/enp3s0/c0:3f:d5:65:1a:22
Sending on Socket/fallback
DHCPDISCOVER on enp3s0 to 255.255.255.255 port 67 interval 3 (xid=0xb977611c)
DHCPDISCOVER on enp3s0 to 255.255.255.255 port 67 interval 5 (xid=0xb977611c)
DHCPDISCOVER on enp3s0 to 255.255.255.255 port 67 interval 13 (xid=0xb977611c)
This is the log on the server side:
Jul 15 16:41:33 ruby dhcpd[17442]: DHCPDISCOVER from c0:3f:d5:65:1a:22 via enp5s0
Jul 15 16:41:33 ruby dhcpd[17442]: DHCPOFFER on 192.168.40.78 to c0:3f:d5:65:1a:22 via enp5s0
Jul 15 16:41:36 ruby dhcpd[17442]: DHCPDISCOVER from c0:3f:d5:65:1a:22 via enp5s0
Jul 15 16:41:36 ruby dhcpd[17442]: DHCPOFFER on 192.168.40.78 to c0:3f:d5:65:1a:22 via enp5s0
Jul 15 16:41:39 ruby dhcpd[17442]: DHCPREQUEST for 192.168.40.57 from 2a:a8:78:ff:95:6f via enp5s0
Jul 15 16:41:39 ruby dhcpd[17442]: DHCPACK on 192.168.40.57 to 2a:a8:78:ff:95:6f via enp5s0
Jul 15 16:41:41 ruby dhcpd[17442]: DHCPDISCOVER from c0:3f:d5:65:1a:22 via enp5s0
Jul 15 16:41:41 ruby dhcpd[17442]: DHCPOFFER on 192.168.40.78 to c0:3f:d5:65:1a:22 via enp5s0
Other devices on the same network, same cable even have no issue getting IPs. Not does this box when it's running another OS.
- I've tried disabling the rfc3442 bits in dhclient.conf. That didn't help.
- I've tried setting the dhcp-client-identifier by hand. That didn't help.
- I've tried an USB based NIC, that dint' get an IP either
- I've tried updating the netplan file as described here: https://superuser.com/questions/1338510/wrong-ip-address-from-dhcp-client-on-ubuntu-18-04 - that didn't work.
I cannot use the wired interfaces on this box, while, before I installed it with Ubuntu, I could. What is going wrong and how can I fix it?
Edit: it's the server. If I plug it into another network, it gets DHCP just fine. Just not from my own Ubuntu 18.04 dhcpd server. Now finding out why.
