[strongSwan] GRE over IPSec issue: ping: sendmsg: Invalid argument

[Tobias Brunner]

Hi Florin,

> One more thing - when I run "ip tunnel add" I get this warning (I don't 
> know whether it matters or not):
> 
> #######################################
> [root at site1-vpn ~]# ip tunnel add gre0 local 10.0.1.254 remote 
> 10.0.2.254 mode gre ttl 255
> ioctl: File exists
> #######################################

It does and it's not a warning.  gre0 is a dummy/default device that's
automatically created by the ip_gre module (can't be modified or
deleted), so you have to name your device differently.

Regards,
Tobias