To use esmtp with mutt add set sendmail="/path/to/esmtp" to your ~/.muttrc and create a ~/.esmtp (see sample.esmtp for an example.) For debugging purposes you may prefer using the follwing shell script. #!/bin/sh LOGFILE=/tmp/esmtp.log echo $0 $@ > $LOGFILE /path/to/esmtp -m $@ >> $LOGFILE exit $? Save it as esmtp.sh and put in you ~/.muttrc set sendmail="/path/to/esmtp.sh" instead. TODO: This would be better handled if done by esmtp itself and controllable by a configuration setting.