OpenSMTPD 7.3.0p0 rc1 builds okay on Slackware 15.0 (stable) but displays this configure warning message:
configure: WARNING: unrecognized options: --with-path-CAfile Testing smtpd failed at first The program started, but stopped immediately with an error message: smtpd[10147]: info: OpenSMTPD 7.3.0-portable starting smtpd[10152]: dispatcher: tls_config_set_ca_file: failed to open CA file '/etc/ssl/cert.pem': No such file or directory smtpd[10148]: smtpd: process control socket closed Slackware 15.0 does not have an /etc/ssl/cert.pem file, but does have a ca-certificates.crt file... So I created a symbolic link from /etc/ssl/cert.pem to the ca-certificates.crt file and smtpd now starts up fine. It works with simple local email. I will modify the build to remove the --with-path-CAfile configure option and add a symbolic link for /etc/ssl/cert.pem I will keep testing and see if it breaks...