GRE Tunnel subnet /29

panthera666

I watched this tutorial: https://www.lowendtalk.com/discussion/156850/howto-tunnel-ddos-protected-ovh-ip-to-vms-in-other-datacenter

And I have problems with the GRE tunnel, I created a VPS on server 2 with IP from the / 29 subnet (x.198), only I can't connect to the VPS. If I try to connect from server 1 to the VPS server created on server 2 it works (ssh x.198).

IP SV1: x.158
IP SV2: x.242
IP /29: x.192/29
Bridge: bridge0

SV1:
ip tunnel add gre1 mode gre remote x.242 local x.158 ttl 255
ip link set gre1 up
ip route add x.192/29 dev gre1

SV2:
ip tunnel add gre1 mode gre remote x.158 local x.242 ttl 255
ip link set gre1 up
ip rule add from x.192/29 table 666
ip route add default dev gre1 table 666
ip route add x.192/29 dev bridge0 table 666
ip addr add x.193/29 dev bridge0

SV 2 - /etc/sysconfig/network-scripts/ifcfg-bridge0
DEVICE=bridge0
TYPE=Bridge
ONBOOT=yes
BOOTPROTO=static
IPADDR="x.194"
NETMASK="x.248"
GATEWAY="x.193"

Abd

Server1 -
Primary IP: x.x.x.x
Additional IP subnet: 10.37.130.88/29

Server2 -
Primary IP: y.y.y.y
bridge(for vps) - vmbr0

Server1:
ip tunnel add gre1 mode gre remote y.y.y.y local x.x.x.x ttl 255
ip link set gre1 up
ip route add 10.37.130.88/29 dev gre1

Server2:
ip tunnel add gre1 mode gre remote x.x.x.x local y.y.y.y ttl 255
ip link set gre1 up
ip rule add from 10.37.130.88/29 table 666
ip route add default dev gre1 table 666
ip route add 10.37.130.88/29 dev vmbr0 table 666
ip addr add 10.37.130.88/29 dev vmbr0

create VMs on Server2 using gateway as 10.37.130.88

RickBakkr

Note that the above does only work when the IPs are statically routed over one of the IPs bound to the server at $provider.

In case you need to 'pull' the traffic from some bigger shared subnet to the VM, you may need proxy_arp to make it work.