Yesterday our internet connection was down for most of the day but my home network as not affected. I tried to login to Plex on my PS3 but could not. Is there a means by which I could have used Plex on a functioning network without an internet connection?
I believe the PS3 needs an internet connection to function.
Here is the Support article that talks about it:
https://support.plex.tv/hc/en-us/articles/200484903-Internet-and-Network-Requirements
Some clients don’t have any other means to ‘find’ a server than to ask plex.tv for its IP address.
Unfortunately the PS3 belongs to this category.
Other clients don’t have this restriction. Usually those clients which have a setting where you can define a plex server IP manually, can be used without internet connection.
Examples: OpenPHT, PMP, the iOS mobile app, ths Samsung Smarthub app, Rasplex.
I may have forgotten a few (sorry - I don’t use all of them).
If used as DLNA player. NO
I was just going to post this myself that it is a frustrating requirement. glad i searched first 
