Not able to connect from different subnet

I got a Home Assistant Blue, so I didn’t install HAOS myself. I’m having an odd networking problem. I can connect to HA (both the web interface and ssh) if I’m on the same subnet. From a different subnet, however, I can ping it, but not connect to the web interface or ssh.

The fact that I can ping from both directions across subnets makes me think that my router/firewall are fine. The log for the ssh addon reports the connection attempt but says it’s timing out before authentication. This makes me feel like HA has some sort of firewall/authentication mechanism that only allows connections from the same subnet?

I’m actually migrating from an RPi and don’t remember running into this issue before. Though, I didn’t copy any configuration files because I wanted a fresh start.

Well, it’s fine for ICMP (ping).
Maybe check you router firewall rules to see if all traffic is allowed between subnets, or just specific one, like ICMP.

And check your subnet masks :wink:

It looks like the problem was gremlins…

I noticed that my laptop had weird network connectivity issues when it was on the same subnet as HA. After messing around a little, I concluded that it had to be a problem with the VLAN configuration on my switches. While I was debugging, the problem went away. But I don’t see any obvious changes I made that would have fixed it.

What was really weird is that seemingly random traffic was getting lost in the ether. Like some websites would work from one subnet but not the other. And some ssh connections I tried looked like they were only being blocked in one direction.