Doggy OS DNS Server

local function loadDNS()
    local dns = {}
    for _, file in ipairs(fs.list("/DNS")) do
        local f = fs.open("/DNS/" .. file, "r")
        local ip = f.readAll()
        f.close()
        dns[file] = ip
    end
    return dns
end

local function logConnection(url, ip)
    local logFile = fs.open("dns_log.txt", "a")
    local logMessage = "URL: " .. url .. ", IP: " .. (ip or "Not found")
    logFile.writeLine(logMessage)
    logFile.close()
    print(logMessage)
end

local dns = loadDNS()

rednet.open("top")  -- Assuming the modem is on the top
print("DNS Server running...")

while true do
    local senderID, url = rednet.receive()
    local ip = dns[url]
    logConnection(url, ip)
    if ip then
        rednet.send(senderID, ip)
    else
        rednet.send(senderID, "404_NOT_FOUND")
    end
end