There's a need for such option, to assure reliability for scipts using smtp client package. I made a simple "experiment": while sending a few mails simply pulled ethernet plug out of the socket - the script went "frozen" for several minutes (didn't measure...), until I plugged it in again. IMHO there should be possibility to give up ("-timeout x", where "-timeout 0" could mean "keep trying unlimited time"), And perhaps it could be improved a bit: to keep the entire script responsible, even in the case of network problems, like loss of connectivity?