I would like to simulate datacenter connectivity network error for DR testing. I have a local network with total of 6 hosts, simulating two datacenters with 3-3 hosts.
I would like to simulate the complete connectivity loss between the two DCs, but leaving intact all network communications within both DCs. (plus me on a seventh host, I would like to SSH to all).
For the simplicity (this in not a security test) all firewall, selinux disabled, everything is open.
I suppose it can be done with firewalld, just (at least for me) seems a bit hard, maybe impossible. I can use firewall-cmd to open a port, then reload, but this is pretty much it. Besides of that, I do not want to reinvent the wheel, in case there is a specialized simple tool for this.