luasocket/test/find-connect-limit

#!/usr/bin/env lua
--[[
Find out how many TCP connections we can make.

Use ulimit to increase the max number of descriptors:

ulimit -n 10000
ulimit -n

You'll probably need to be root to do this.
]]

socket = require "socket"

host = arg[1] or "google.com"
port = arg[2] or 80

connections = {}

repeat
	c = assert(socket.connect(hostip or host, 80))
	table.insert(connections, c)

        if not hostip then
            hostip = c:getpeername()
            print("resolved", host, "to", hostip)
        end

	print("connection #", #connections, c, "fd", c:getfd())

until false