Welcome to the most active Linux Forum on the web.
Go Back > Forums > Linux Forums > Linux - Networking
User Name
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.


  Search this Thread
Old 05-25-2004, 12:16 PM   #1
LQ Newbie
Registered: Dec 2002
Posts: 2

Rep: Reputation: 0
dhcp w/ comcast not setting default route

After rebooting for the first time in a while, I had some problems getting my network working again. I have a Comcast cable modem, and when bringing up the network connection, dhclient was able to get an ip but it wasn't setting a default route. I've managed to solve this by setting the route manually every time I have to bring the interface back up, but I'd feel better if I found the source of the problem instead of just a workaround.

After bringing up the interface, the following routes were set:
[root@annulus dhcp]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface   U     0      0        0 eth0       U     0      0        0 lo
with my ip address being

Looking in /var/lib/dhcp/dhclient.leases:
lease {
  interface "eth0";
  filename "mdcm315_v1_silver_c01";
  option subnet-mask;
  option routers;
  option dhcp-lease-time 604800;
  option dhcp-message-type 5;
  option dhcp-server-identifier;
  option domain-name-servers,,,;
  option domain-name "";
  renew 4 2004/5/27 07:33:22;
  rebind 0 2004/5/30 07:14:03;
  expire 1 2004/5/31 04:14:03;
you can see that dhclient was getting router information. Unfortunately, this ip address was not reachable with the routing tables set up the way they were. By setting the default gateway manually to, everything works fine.

So either this is a bug/config problem with dhclient (searching the dev lists didn't turn anything up) or a config problem with Comcast's dhcp server which causes it to send out the wrong router.

Oh, and when I boot into win2k, the network comes up just fine - which means either the problem is with dhclient OR windows automagically works around the problem by trying alternative gw's until it finds one that works ???

Anybody else have this problem or have any insight?


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
DHCP default route attached to loopback interface chiefdan Linux - Hardware 2 12-06-2005 06:08 PM
Not getting a default route from DHCP BadTA Linux - Wireless Networking 16 12-02-2005 03:56 AM
dhclient not setting default gateway - no WAN route kadissie Linux - Networking 2 03-10-2005 05:55 AM
Route to subnet exists but I get "Network unreachable" when adding default route fciuffani Linux - Networking 4 08-18-2004 03:11 PM
Linux router - setting up a DMZ or default machine to route to Rooboy Linux - Networking 12 02-18-2004 04:44 PM > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 07:19 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration