Hello,
I have the following setup as in the schematic.
Router1 has a 10G uplink to the internet, no BGP, no IP space announcements etc - just a single WAN IPv4 for now.
Router2 has 1G uplink, announces a /24 via BGP.
The two routers are in two different datacenters in the same city - rtt between them is less than 1ms.
What I want to do is move server2 which is on VLAN2 (x.x.x.65/28) to the other datacenter, but I want to continue using the same subnet.
(VLAN2 or the particular subnet are not used from any other servers - it's exclusive to server2)
I tried to create an EoIP tunnel between the two routers, to extend the l2 broadcast domain, but it's acting like a hub - and all traffic going from router2 to switch2 also goes over the eoip tunnel to router1. So even though there's nothing behind router1 at the moment, I see 100-200mbps inbound traffic on router1 over the eoip link (when you look at the traffic graph it's like 1:1 the same traffic that goes to switch2).
When I connected an RPi4 to router1, and used one of the available IPs of one of the VLANs on router2, while everything worked right away and I had network connectivity etc, it felt very unstable - connections would drop, and I could not get more than 260Mbps with iperf.
So my next thought was to setup a GRE tunnel between the two routers, but I'm not sure if this can be done with a subnet smaller than /24 using public IPs?
I understand that I will need to setup an IP in each side of the tunnel of a /30 subnet. ie 10.10.10.1/30 for router1 and 10.10.10.2/30 for router2.
Then I will need to delete the VLAN and IP address from router2 and create it on router1.
Finally I would add a static route on router2 for x.x.x.65/28 dst 10.10.10.1
How will I route all outbound traffic from server2 through the GRE tunnel and out to the internet via router2, without affecting router1 to reach the internet via the WAN?
Should I use routing-mark for this?
If you have any suggestions or other ideas about how I can do this, let me know.
Thanks!