[Question]: Network between two services / VMs

[Foosec]

Is your question not already answered in the FAQ?

• I made sure the question is not listed in the FAQ.

Is this a general question and not a technical issue?

• I am sure my question is not about a technical issue.

Question

How would one approach creating i.e a Proxmox cluster via this?
Where the VMs need to communicate between each other but also the localhost needs access to them?

Tried via passt, slirrp, not having much success, the VM's can reach via service names but some software requires directly by IP.