local playersConnecting = {}
local playersBanned = {"ip:10.10.10.10", "ip:10.10.10.11"}

AddEventHandler( "playerConnecting", function( playerName, setCallback )
    table.insert( playersConnecting, bit32.band( source, 0xFFFF ) + 1 )
end)

-- GetPlayerEP does not handle NetIDs, only PlayerIDs. Server LUA does not have Citizen.CreateThread nor Wait
-- so we use this method to periodically check NetIDs converted to PlayerIDs (NetID & 0xFFFF + 1).
-- Usually triggered when the PlayerID is actually added to the server ~600ms after connecting.
local function checkPlayersConnecting()
    if #playersConnecting > 0 then
        local EP = GetPlayerEP( playersConnecting[1] )

        if EP ~= nil then
            EP = "ip:" .. EP:Split( ":" )[0]

            for k,v in pairs( playersBanned ) do
                if v == EP then
                    DropPlayer( playersConnecting[1], "You are banned." )
                    break
                end
            end

            table.remove( playersConnecting, 1 )
        end
    end

    SetTimeout( 175, checkPlayersConnecting )
end

SetTimeout( 1, checkPlayersConnecting )