PSA: If a host doesn't appear on your client and you have Portmaster installed: check this

[majima-everywhere]

Just putting this out there in case it saves someone the months of frustration I went through

I had an issue where one specific PC would not appear to clients on my local network, while other machines worked perfectly out of the box. I went deep into troubleshooting:
-Router configs
-Windows firewall
-Network + sharing settings
-Privacy settings
-DNS, resets, etc.

... Nothing worked. I eventually gave up and just accepted it

Fast forward months later, I ran into a different issue = Couldn't access sites like https://1.1.1.1/ (I wanted to download Cloudflare WARP) or https://8.8.8.8/ (those sites are accessible on other computers and my phones connected to the same network)

1. Pinging the servers worked
2. DNS resolution worked
3. ! But HTTPS requests (curl -v) would never complete !
4. Wireshark showed something even weirder: The request never left my PC !!

At that point I knew: Something on my machine was intercepting/blocking traffic before it even hit the network, and it wasn't Windows' firewall. After a lot of digging, I finally found the culprit and it was Portmaster

Even though the app itself wasn't running, its service was running in the background at startup

When I opened Portmaster, I saw those IPs were being blocked.. and no obvious indication unless you open the app

Uninstalling Portmaster or set its service from automatic to manual solved everything :
-Blocked sites became accessible
-Host started appearing on clients
-Local network communication worked again
^^ Basically all the "unexplainable" network issues I had for months disappeared ;-;

Tl;dr host doesn't show up on your client and you have Portmaster installed on your computer. Uninstall it or set its service launch option to manual in stead of automatic.

I lost a ton of time chasing this across router, windows (firewall and settings), and network layers

Hopefully this helps someone avoid the same rabbit hole :D