Stuart Henderson wrote: > see kern_exec.c line 600
Thanks for the nudge. I managed to get to the bottom of this. It turns out Alpine relies on the (ironically named) -bs mode of sendmail, which is not implemented in OpenSMTPD. Per sendmail documentation, -bs is described as: Use the SMTP protocol as described in RFC821 on standard input and output. This flag implies all the operations of the -ba flag that are compatible with SMTP. If I understand correctly, this is implementing SMTP over a pipe. I also think the man page of sendmail(8) is a bit misleading: To maintain compatibility with Sendmail, Inc.'s implementation of sendmail, various other flags are accepted, but have no effect. Well, not really. Unfortunately what happens is smtpctl will swallow the -bs flag and just sit there waiting on stdin while Alpine is also waiting for an SMTP greeting on stdout which is never sent and nothing happens. I believe that explains the hang; sendmail will do the exact same if you do not pass it the -bs flag. Since OpenSMTPD does not implement this functionality, and no one has asked for it in the > 10 years this bug has existed, I propose: 1. patch the default /etc/pine.conf in the Alpine port using the patch I provided so Alpine prefers to connect to the local smtpd over TCP 2. I will be submitting a patch against smtpctl so passing -bs errors out so this doesn't happen again. Regards Lloyd
