No available packages.
I had installed pfSense 2.4.2 yesterday, after I configured LAN adapter, I tried to install a package (Squid) but the list of available packages is empty. What I need to do for install it?
Usually that's because it cannot reach the package server for some reason.
Does it have a valid WAN connection?
It is able to check for firmware updates on the dashboard?
check under System | Update and the 'Update Settings' Tab…
see what the 'Branch' is set to .... for 2.4.xx it should be 'stable'.
Be aware that if you change this setting it will not take effect until you reboot the router.
That setting actually applies immediately. You might have to trigger a refresh though by reloading the System Update tab or refreshing the firmware check on the dashboard or running 'pkg update' at the CLI.