Can I download mods for Factorio, without a Factorio account?
Unfortunately not. Factorio does not permit you to access the downloads for any mods on mods.factorio.com without logging in.
ServerFlex
How do I install mods on a Factorio server?
The ServerFlex Control Panel has 1-Click support for Factorio mods directly from the mods.factorio.com site. Start by heading over to your Factorio server in the Control Panel, and find the navigation item called Mods.
How do I change the maximum players on a Factorio server?
To change the maximum number of players of your Factorio server, head to the Settings tab on the Control Panel. If you do not want to limit players change the value to 0.
Find your Factorio API Token to Authenticate
In order to set your server to be public, or to download mods - you will need to authenticate your Factorio account with your server.
How do I whitelist players on a Factorio server?
The default behavior of Factorio is to allow anybody onto your server, this also applies if a player knows or guesses your server password. It is advisable to whitelist which players can connect to your server to protect from griefers.