Good news! You can whitelist exceptions by IP/subnet
Go into Plex Settings, then Settings > Network (show advanced). Scroll down to "List of IP addresses and networks that are allowed without auth"
"Comma separated list of IP addresses or IP/netmask entries for networks that are allowed to access Plex Media Server without logging in. When the server is signed out and this value is set, only localhost and addresses on this list will be allowed."
Put your local subnet and netmask into that (e.g. "192.168.1.1/255.255.255.0") and you should be all good
FYI, I also have "Secure Connections" set to "Preferred", but I don't know if that makes a difference for this or not
Good news! You can whitelist exceptions by IP/subnet
Go into Plex Settings, then Settings > Network (show advanced). Scroll down to "List of IP addresses and networks that are allowed without auth"
"Comma separated list of IP addresses or IP/netmask entries for networks that are allowed to access Plex Media Server without logging in. When the server is signed out and this value is set, only localhost and addresses on this list will be allowed."
Put your local subnet and netmask into that (e.g. "192.168.1.1/255.255.255.0") and you should be all good
FYI, I also have "Secure Connections" set to "Preferred", but I don't know if that makes a difference for this or not