GRE tunneling between two Linux box working as router

[monu_1]

I have two Linux Box (lets say LB1, LB2) working as routers for two different network each.
LB1 have two ethernet cards & configuration is
Eth0 IP 10.0.1.1
Sub mask 255.255.255.0

Eth1 IP 172.16.17.18
Sub mask 255.255.255.0
Gateway 172.19.20.21

LB2 have also two ethernet cards & setting is as

Eth0 IP 10.0.2.1
Sub mask 255.255.255.0

Eth1 IP 172.19.20.21
Sub mask 255.255.255.0
Gateway 172.16.17.18

Now my question is how to configure these two boxes (i.e. two different networks) to communicate through GRE Tunneling?

What are the packages and modules to install for GRE tunneling?

Pls suggest commands which I have to run to configure GRE tunneling on these two Linux boxes, which are working as router.

Thanks in Advanced.
MKS

[Matti_Kurkela · Accepted solution]

You'll need the "ip" command (the central part of the "iproute2" tools).

You did not tell us the name and version of your Linux distribution(s), so it's kind of difficult to find out the exact package name for you.

Many modern Linux distributions install the "ip" command by default. If any kernel modules are needed, the system can probably load them automatically. Those modules should be included in the standard kernel package of your Linux distribution(s).

A Google search with keywords "Linux GRE tunnel" seems to find a lot of very clear instructions...

for example:
http://www.cerritoslug.org/tutorials/gre_tunneling.html
http://www.linux.com/base/ldp/howto/Adv-Routing-HOWTO/lartc.tunnel.gre.html

MK