Download your favorite Linux distribution at LQ ISO.
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 07-16-2007, 12:02 PM   #1
LQ Newbie
Registered: Jul 2007
Posts: 2

Rep: Reputation: 0
Gre Tunnel Questions

Hey I'm trying to setup a GRE tunnel in a test setup and I just had a few questions.

Do both end points on a gre tunnel have to be on different subnets?

I was under the impression that you should be able to tunnel layer 2 traffic which doesn't seem like it would work if your on different networks.

Also is it necessary to have IP's on the gre interfaces?

All the example setups I've found have IP's on them but I thought that the idea of the tunnel was similar to having a bridge connecting the two sides so an IP would be optional.
Old 07-17-2007, 07:05 AM   #2
Registered: Jun 2007
Posts: 359

Rep: Reputation: 34

well, i'm not trying to teach you
why we need different subnet? in routing there is a mechanism called Split Horizon.
The routers get confuse when seeing 2 identical networks. it cant determine which way to pick the route prior forwarding the packet. so the router stops its function.
the same goes in tunneling - even in theory - your Q is correct.

and, the good thing is for monitoring - you know which traffic from and to

Old 07-18-2007, 12:17 PM   #3
LQ Newbie
Registered: Jul 2007
Posts: 2

Original Poster
Rep: Reputation: 0
Thanks, I finally got the gre tunnel working it doesn't do exactly what I'd hoped but it works


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
GRE Tunnel Not Working doctorcisco Linux - Networking 2 04-19-2009 05:29 AM
dhcp over GRE tunnel fadey Linux - Networking 0 04-29-2007 08:12 AM
gre tunnel with keys for different sessions sureshchandak Linux - Networking 0 06-13-2006 12:20 PM
gre tunnel problem sixone Linux - Networking 3 05-30-2005 11:57 AM
Question about a GRE Tunnel zerounu Linux - Networking 1 03-09-2004 09:04 AM > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 05:56 PM.

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
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration