OVH to Hetzner GRE Tunnel Working, But There Are Some Issues

KeljiX

Hello Everyone,

I am trying to make OVH IPv4 addresses usable on Hetzner. This way, I get OVH protection and don't have to obtain IPv4 addresses from Hetzner.

The GRE tunnel IPv4 addresses I obtained from Noez.de work flawlessly on Hetzner, and I can distribute them perfectly to my virtual servers.

However, when distributing the server and IPv4 addresses I obtained from OVH, I don't experience issues locally but do encounter problems on the public network.

First of all, please don’t refer to the following topics as I’ve already researched and tried them:

https://wiki.buyvm.net/doku.php/gre_tunnel
https://lowendtalk.com/discussion/156850/howto-tunnel-ddos-protected-ovh-ip-to-vms-in-other-datacenter/p1
https://lowendtalk.com/discussion/185975/ip-tunneling-from-ovh-to-hetzner

Noez.de directly routes the IPv4 addresses to my endpoint server, and with the commands below, I can accept them and route them to the network interface I created without any issues. This way, anyone with that network interface can use the IPv4 addresses (without needing a special IPv4 address).

variables:

noez_ipv4 = "22.22.22.22"
special_nonexistent_gateway_address = "222.222.222.1"
created_interface = "ens224"

commands:

ip rule add from noez_ipv4 table 20 prio 1
ip addr add special_nonexistent_gateway_address/24 dev created_interface
ip route add default src special_nonexistent_gateway_address dev gre1 table 20

With these commands, my router server is ready. When I select this ens224 network adapter for my virtual servers, they can start using the 22.22.22.22 IPv4 address.

I don't know how Noez achieved this and would like to learn. Is there anyone who can help me with this?

BuyVM does this via NAT, but GRE tunnel servers can directly connect to each other.

For example, let’s say BUYVM endpoint server: 1.1.1.1 and the endpoint server using the IP: 2.2.2.2.

When using the BuyVM NAT method, when we connect to 1.1.1.1, we are actually connecting to 2.2.2.2, but this happens directly between the two servers. I don’t want this. Noez seems to have managed this and I’m curious how they did it. Because when I connect to Noez’s endpoint server, my endpoint server is not reachable. However, I can use Noez’s IPv4 addresses without any issues.

RickBakkr

Are the IPs routed to your OVH server? That is, not using some virtual MAC / bridging shenanigans? ;-)

What you need:

1. get IPs routed to server A
2. set up a tunnel between server A and B with a /31 subnet (2 IPs; not a /24 ;-) )
3. route your IPs over the tunnel on server A to the 'internal' IP on server B
4. set up the ip rule/ip route (the ones you shared) to override routing on server B, allowing for packets to return over the tunnel
5. You're done.

If you require help .. please feel free to DM me with the exact IPs of both servers, and your routed range, and I'll help you get sorted :-)

Andru

@KeljiX said:
Hello Everyone,

I am trying to make OVH IPv4 addresses usable on Hetzner. This way, I get OVH protection and don't have to obtain IPv4 addresses from Hetzner.

The GRE tunnel IPv4 addresses I obtained from Noez.de work flawlessly on Hetzner, and I can distribute them perfectly to my virtual servers.

However, when distributing the server and IPv4 addresses I obtained from OVH, I don't experience issues locally but do encounter problems on the public network.

First of all, please don’t refer to the following topics as I’ve already researched and tried them:

https://wiki.buyvm.net/doku.php/gre_tunnel
https://lowendtalk.com/discussion/156850/howto-tunnel-ddos-protected-ovh-ip-to-vms-in-other-datacenter/p1
https://lowendtalk.com/discussion/185975/ip-tunneling-from-ovh-to-hetzner

Noez.de directly routes the IPv4 addresses to my endpoint server, and with the commands below, I can accept them and route them to the network interface I created without any issues. This way, anyone with that network interface can use the IPv4 addresses (without needing a special IPv4 address).

variables:

noez_ipv4 = "22.22.22.22"
special_nonexistent_gateway_address = "222.222.222.1"
created_interface = "ens224"

commands:

ip rule add from noez_ipv4 table 20 prio 1
ip addr add special_nonexistent_gateway_address/24 dev created_interface
ip route add default src special_nonexistent_gateway_address dev gre1 table 20

With these commands, my router server is ready. When I select this ens224 network adapter for my virtual servers, they can start using the 22.22.22.22 IPv4 address.

I don't know how Noez achieved this and would like to learn. Is there anyone who can help me with this?

BuyVM does this via NAT, but GRE tunnel servers can directly connect to each other.

For example, let’s say BUYVM endpoint server: 1.1.1.1 and the endpoint server using the IP: 2.2.2.2.

When using the BuyVM NAT method, when we connect to 1.1.1.1, we are actually connecting to 2.2.2.2, but this happens directly between the two servers. I don’t want this. Noez seems to have managed this and I’m curious how they did it. Because when I connect to Noez’s endpoint server, my endpoint server is not reachable. However, I can use Noez’s IPv4 addresses without any issues.

Try to ask Chatgpt or Copilot. You'll be amazed how fast and correct answer you'll get