Zzoomm Static IP query

Myself and a colleague both have static IP addresses from Zzoomm.

Both connections are DHCP based and get a subnet mask of 255.255.252.0 - placing us on the same network...

As a result there's no way to route traffic between the two addresses, meaning VPN's, etc are a no-go.

But to confirm that Zzoomm haven't made an error with our connections could anybody else with a Zzoomm static address confirm they are also in the address range 84.18.228.1 - 84.18.231.254 please ? (we're both South Yorkshire based in case region plays a part in this).

(Zzoomm themselves have blamed our respective configs rather than accepting there might be a problem).

Cheers.

Can you ping your colleague's IP address and get a reply?

If you are on the same network, then there is no routing required. Routing is by definition between different subnets.

That's not to say that Zzoomm have not got something in place to blackhole traffic between customers. Can you get this site's BQM to work for both connections? That will prove that ICMP [I think] is getting through from totally outside, pinging between routers will then show that you are working across the subnet.

This is a side effect of a DHCP connection over PPPoE - there's no broadcast traffic permitted over the /22 so each client can only speak to the gateway.

One of the customers will have to request a change of subnet, which may not even be possible depending on how Zzoomm structure their network.

You can bodge your way around this by tunnelling IPv4 over IPv6

In reply to a post by jpm:

This is a side effect of a DHCP connection over PPPoE - there's no broadcast traffic permitted over the /22 so each client can only speak to the gateway.

Interesting. This looks like a breach of the implied Internet Services contract for IPv4, to provide connectivity to all public IPv4 addresses

In reply to a post by jpm:

One of the customers will have to request a change of subnet, which may not even be possible depending on how Zzoomm structure their network.

Looks like a solution, which would work and require zzoomm to do whatever is required given the implied IPv4 contact

On each router, try adding a static route to the other party's IP address via the gateway

e.g. say:
you are 84.18.228.42 with gateway 84.18.228.1
they are 84.18.228.123 with gateway 84.18.228.1

On your router, add a route to 84.18.228.123/32 via 84.18.228.1
On their router, add a route to 84.18.228.42/32 via 84.18.228.1

In reply to a post by jpm:

One of the customers will have to request a change of subnet, which may not even be possible depending on how Zzoomm structure their network.

Tailscale/Tailnet? That would work, depending on what latency they require, and keep the pesky ISP out of the conversation

If you can't do that, it may be possible to give the router the usual fixed IP address with the suffix /32 or mask 255.255.255.255, and not accept that information from DHCP.

What implied contract, please?