Problem
This happens with several services but I’ll use SSH just for the example. I have host A and host B connected to a Zerotier network A. If I try to SSH from host A to host B I get “No route to host”. If I ping from both hosts to each other, the first couple of pings fail and then start working. Once I’m able to ping, I can SSH successfully and uninterrumpted
Setup
At that moment, before doing anything: both hosts are connected to the internet. No proxy or firewall is in place. In Zerotier dashboard I see both hosts online. No rules or whatsoever on zerotier side. No power saving or similar configured on each host. Zerotier installed version is the latest version, on Windows hosts the service is running.
Workaround
If I log in into each host and ping each others zerotier IP, the first pings fail but eventually start receiving a reply on both hosts. Once that works, I can normally SSH.
As I said, this is not just for SSH: RDP and HTTP also fail. On Windows hosts I enabled ICMP to be able to ping to. It happens between windows-linux, linux-windows, windows-windows, linux-linux.
Saw this discussion from before mentioning an issue in github but no clue what that issue is Node looks connected but no ping and no connection
Also searched for issues in github and couldn’t find anything.