How to fix or bypass the DHCP handshake to get an IP address

Question

My linux box can't seem to get a DHCPOFFER from my router. This is blocking me from getting internet access on the linux box.

Here's the setup: I have two computers, a linux box called mocha and a windows box called latte. I'm trying to use latte get more information about what's wrong with mocha. I have a Netgear WNR2000 v3 router.

Mocha

• had fully functional internet access until a recent reboot
• (thinks it) is broadcasting DISCOVER messages every 15 seconds or so
• gets no answer to dhcping -v
• is running dhcpdump, which is dumping
  • the REQUEST, ACK, and INFORM messages broadcast between the router and latte
  • DISCOVER messages broadcast by itself (mocha)

Latte

• is connected by ethernet to the same router as Mocha and has fully functional internet access
• is running wireshark, filtered for "bootp"
  • I expect it should see all DHCP messages that are broadcast on the network, including the DISCOVER messages (supposedly) broadcast by mocha
  • It is actually seeing only the REQUEST, ACK, and INFORM messages being broadcast and unicast between itself and the router.

In conclusion, I think mocha isn't getting an OFFER message because its DISCOVER messages aren't getting through. What can I do to make them get through? Or is there a way I can skip DHCP discovery and fabricate a working IP address for it in order to get internet access?

Answer 1

If by 'fabricate a working IP address' you mean assign a static IP then sure. Just edit your interface config file at /etc/sysconfig/network-scripts and change it from dhcp to none. For example:

# cat /etc/sysconfig/network-scripts/ifcfg-eth0
TYPE=Ethernet
NOZEROCONF=yes
BOOTPROTO=none
DNS1=X.X.X.X  <= dns server
DNS2=X.X.X.X  <= dns server
DEFROUTE=yes
NAME=eth0
DEVICE=eth0
ONBOOT=yes
IPADDR=X.X.X.X  <= your assigned IP
PREFIX=24
GATEWAY=X.X.X.X <= the default gateway
NM_CONTROLLED=no

then just execute command:

service network restart