LinuxQuestions.org
Register a domain and help support LQ
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Networking
User Name
Password
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.

Notices

Reply
 
Search this Thread
Old 08-16-2004, 03:06 AM   #1
sixone
LQ Newbie
 
Registered: Aug 2004
Posts: 2

Rep: Reputation: 0
gre tunnel problem


Hi

I set-up a gre tunnel between two linux boxes.
A short diagram is like this

lan1 -> router1 ----- router2 <- lan2

The tunnel works fine, i can ping from lan1 to lan2 but the problem is the speed between lan1 and lan2 is lower than it supposed to be
If i log in to router1 and transfer something from router2 or lan2 it is working at maximum speed, 1024kbits/s. The problem is if i log in to a computer in lan1 and try to transfer something either from router2 or lan2 is working very poor, with 256kbits or worse.
I also tried to add that line in iptables with --clamp-mss... same no luck
I ran out of ideas and this is driving me crazy. PLease help!

Last edited by sixone; 08-16-2004 at 03:08 AM.
 
Old 08-17-2004, 11:01 AM   #2
peter_robb
Senior Member
 
Registered: Feb 2002
Location: Szczecin, Poland
Distribution: Gentoo, Debian
Posts: 2,458

Rep: Reputation: 47
What's the MTU on the GRE tunnel?

You may need to set the LAN MTU to match this to avoid fragmenting packets before they are sent..
 
Old 08-18-2004, 01:13 AM   #3
sixone
LQ Newbie
 
Registered: Aug 2004
Posts: 2

Original Poster
Rep: Reputation: 0
MTU on tunnel is 1476 (its is GRE). I tried to set-up the MTU on network card 1476 and on a Windows client also.. Same, there is no difference.. Meanwhile i've installed freeswan which is setting the mtu somwhere around 16000.. The things are exactly the same, there is no change in good or bad with the speed.. And i've tried this on three linux distributions with three types of kernel.
 
Old 05-30-2005, 11:57 AM   #4
jarod
LQ Newbie
 
Registered: Jul 2003
Location: .ro
Posts: 10

Rep: Reputation: 0
I also have a problem with a GRE tunnel (my first one ) so I decided to post it here. Here's how things look:

networkA is 192.168.1.0/24 with routerA that has eth0 (ip a.b.c.d) and br0 (ip 192.168.1.1)
networkB is also 192.168.1.0/24 (that's the tricky part ) with routerB that has eth0 (ip e.f.g.h) and eth1 (ip 192.168.1.10).

After reading a while about it, I found out that I had to use proxy_arp to get things to work. So here's what i did:
Code:
ip tunnel add tun0 mode gre remote a.b.c.d local e.f.g.h ttl 255
ip link set tun0 up
ip addr add 192.168.1.10 dev tun0
ip route add 192.168.1.1 via 192.168.1.10 dev tun0
and, on the other router, the same thing, but mirrored (switched remote with local). Pinging from routerA to routerB gives me only icmp echo requests on both end of the tunnel (tun0 monitored with tcpdump). My guess is that the problem is with that last route I added, but I can't figure it out. ip_forward is 1, proxy_arp is 1.

P.S.: does it matter what IP do I assign to tun0? My guess is no, but I want to make sure.
 
  


Reply


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
IP tunnel problem marcinbu Linux - Networking 2 03-09-2012 01:46 AM
Vpn poptop - CTRL: PTY read or GRE write failed (pty,gre)=(5,6) dezeque Linux - Networking 8 12-11-2009 01:56 PM
GRE keepalives. How can a SUSE 9.0 Linux box send GRE keepalives? dlef Linux - Networking 1 06-28-2005 12:00 PM
Question about a GRE Tunnel zerounu Linux - Networking 1 03-09-2004 09:04 AM
ipv6 tunnel problem routergeek Linux - Networking 0 05-09-2003 05:25 PM


All times are GMT -5. The time now is 02:02 AM.

Main Menu
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration