i cannot find our where you got this timeout() method from. it's neither part of the Client packet, nor of any of the modules you require. the 'Timeout' value is an argument to the constructor of an IO::Socket::INET instance, which is basically all the Net::SMTP::Server package is wrapped around. the pod from IO::Socket::INET tells us that it stands "for various operations", whatever this means. however, all of the perl socket API in the end results in calls to system functions (socket(), accept(), listen() etc.), and none of these system functions requires a timeout argument.