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Old 07-11-2006, 08:48 AM   #1
Registered: Nov 2003
Posts: 70

Rep: Reputation: 17
GRE Tunnel Not Working


I am having a problem bringing up a GRE tunnel between my wrt54gs running OpenWRT and a Cisco router. I've done what I can see to do from my googling, but it's still not working. Here's what I have on the Linksys:

root@OpenWrt:/etc# ip tunnel show
gre0: gre/ip remote any local any ttl inherit nopmtudisc
gre1: gre/ip remote local ttl 255

root@OpenWrt:/etc# ip addr show
7: gre0@NONE: <NOARP> mtu 1476 qdisc noop
link/gre brd
10: gre1@NONE: <POINTOPOINT,NOARP,UP> mtu 1476 qdisc noqueue
link/gre peer
inet scope global gre1

root@OpenWrt:/etc# ip route show dev gre0 proto kernel scope link src dev gre0 scope link dev br0 proto kernel scope link src dev vlan1 proto kernel scope link src
default via dev vlan1
default via dev br0 scope link

root@OpenWrt:/etc# ping
PING ( 56 data bytes

--- ping statistics ---
6 packets transmitted, 0 packets received, 100% packet loss

root@OpenWrt:/etc# ping
PING ( 56 data bytes

--- ping statistics ---
5 packets transmitted, 0 packets received, 100% packet loss

root@OpenWrt:/etc# ifconfig
gre0 Link encap:UNSPEC HWaddr 45-DE-A0-28-00-00-00-00-00-00-00-00-00-00-00-00
inet addr: P-t-P: Mask:
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:21 dropped:0 overruns:0 carrier:21
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

Rather clearly the problem is on layer 2, since the virtual interface is taking "carrier errors," even though all the physical interfaces are up and running.

Hopefully it's some stupid simple thing I overlooked. As my nick indicates, I know alot more about Cisco's than Linux! I'm 100% sure the config on the Cisco is correct.

Old 07-12-2006, 04:58 PM   #2
Registered: Nov 2003
Posts: 70

Original Poster
Rep: Reputation: 17

Any ideas out there? My forehead is wearing a hole in the wall here!

Old 04-19-2009, 05:29 AM   #3
LQ Newbie
Registered: Apr 2009
Posts: 1

Rep: Reputation: 0
Try to disable firewall for testing, it worked for me!

Now find te problem in the firewall


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