Using GRE Ethernet tunnel
GRE stands for Generic Routing Encapsulation and it is a standard protocol defined in [RFC2784] and [RFC1701]. So far it has been used mainly for building IPv4 tunnels over IPv4. In this article, we will show you how to use it for building Ethernet tunnels over IPv4 using “Transparent Ethernet Bridging”.
First of all, you need a recent kernel that understand the gretap stuff (this feature has been introduced on 2008-10-09 in net/ipv4/ip_gre.c, kernel revision v2.6.27-rc9-1078-ge1a8000, ie since 2.6.28). You need to enable :
[*] Networking support --->
Networking options --->
<M> IP: GRE tunnels over IP
The kernel module itself is called ip_gre :
# modprobe ip_gre
Next, you need a recent iproute2 package that understand the gretap stuff (this feature has been introduced on 2008-10-09 in ip/link_gre.c). iproute2 is available through git at :
$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/shemminger/iproute2.git
Then, you just need to create the tunnel itself :
# ip link add mygre type gretap remote 192.168.30.153 local 192.168.30.244
Of course, you need to do the reverse on the other side of the tunnel :
# ip link add mygre type gretap remote 192.168.30.244 local 192.168.30.153
To remove the interface :
# ip link del mygre
For more information on GRE Ethernet : http://projects.kwaak.net/twiki/bin/view/Misc/IpRoute
For more information on iproute2 : http://www.linuxfoundation.org/en/Net:Iproute2