is it possible to bridge virtual devices (ie. a GRE tunnel)?

is it possible to bridge virtual devices (ie. a GRE tunnel)?

[Chris Friesen]

I want to set up two physically separate LANs with the same network 
address and logically bridge them using some kind of tunnel over an IP 
network.

I was hoping to somehow combine bridging with GRE tunnels in the kernel 
to accomplish this, but I haven't been able to find out for sure if the 
current kernel bridging code can handle a tunnel device as one of the 
bridge elements.

Can anyone give the definitive answer for this?

Thanks,

Chris

-- 
Chris Friesen                    | MailStop: 043/33/F10
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Re: is it possible to bridge virtual devices (ie. a GRE tunnel)?

[Kevin P. Fleming]

Chris Friesen wrote:
> 
> I want to set up two physically separate LANs with the same network 
> address and logically bridge them using some kind of tunnel over an IP 
> network.
> 
> I was hoping to somehow combine bridging with GRE tunnels in the kernel 
> to accomplish this, but I haven't been able to find out for sure if the 
> current kernel bridging code can handle a tunnel device as one of the 
> bridge elements.
> 
> Can anyone give the definitive answer for this?
> 
> Thanks,
> 
> Chris
> 

I don't believe you'd be able to use GRE tunnels, as they are not an "Ethernet" 
type of tunnel.

However, I run a network with three physical locations, bridged over TAP-type 
tunnels using VTUN (vtun.sourceforge.net). These are Ethernet-type tunnel 
devices, so the bridge code just sees them as if it was any other Ethernet 
network interface.

In addition, I use ebtables to control what traffic gets bridged across the 
tunnels, so extraneous broadcast/multicast traffic stays where it is supposed to.