topic probelem adding default gateway in Operating System - Linux

probelem adding default gateway

Deoncia Grayson_1 — Tue, 07 Jun 2005 15:10:08 GMT

Here is my problem, every time I try to add the default gateway, it doesn't add it properly the command I use is

route add default gw (ip address) dev eth0

and when I do a netstat -nar to see the routing tables. I see instead of default and the ip address, it gives 0.0.0.0, the ip address and a genmask of 0.0.0.0.. I even tried adding the gateway through netconf to no avai.

Re: probelem adding default gateway

Maxim Rozin — Tue, 07 Jun 2005 16:10:43 GMT

Hello Deoncia Grayson,

In RedHat, the default gateway is written in /etc/sysconfig/network. After you edit that file, restart network (/etc/init.d/network restart).
If you don't write the default gateway in that file, then after reboot, it wont be configured.

Max.

Re: probelem adding default gateway

Stuart Browne — Tue, 07 Jun 2005 17:44:17 GMT

'netstat -nr' will show the default route as:

0.0.0.0 0.0.0.0 UG 0 0 0 eth0

using that format.

The Destination is be 0.0.0.0 with a genmask (netmask) of 0.0.0.0 as it has to match *EVERYTHING*.

It's also why the route will always appear at the end of the routing list.

If you have multiple lines with the destination of '0.0.0.0', then you have multiple default routes. Make sure to remove the incorrect ones.

The file 'maxim' mentions is if you use 'netconf' and only have one interface. If you have multiple interfaces, the keyword 'DEFAULT' can appear within the individual interface's configuration file (usually '/etc/sysconfig/network-scripts/ifcfg-' or '/etc/sysconfig/networking/' somewhere).

Re: probelem adding default gateway

Gopi Sekar — Wed, 08 Jun 2005 02:03:03 GMT

see whether this is what you are getting:

Destination Gateway Genmask Flags MSS Window irtt Iface
0.0.0.0 x.x.x.x 0.0.0.0 UG 0 0 0 eth0

as you see the first entry is destination IP address range match. 0.0.0.0 is a wild card which will match all ip address ranges and x.x.x.x shows the gateway server ip address.

Hope this helps,
Gopi

Re: probelem adding default gateway

Suraj Singh_1 — Wed, 08 Jun 2005 05:14:44 GMT

There is nothing wrong in 0.0.0.0/0.0.0.0, this refers to everything.

Look for the Flags column. an UG in the row containing 0.0.0.0 0.0.0.0 shows that the IP present in the Gateway column is indeed the default gateway.

You may check this by issuing a traceroute command to an unknown IP, and see what is the first hop in the o/p.

eg, traceroute 1.2.3.4

Regards

Re: probelem adding default gateway

Deoncia Grayson_1 — Wed, 08 Jun 2005 13:47:39 GMT

Everyone response was greatly appreciated but I went the first guys response and it worked just fine... Thanks guys!