qmail-popup - read a POP username and password

SYNOPSIS

       qmail-popup hostname subprogram

DESCRIPTION

       qmail-popup  reads  a  POP  username and password from the
       network.  It then runs subprogram.

       qmail-popup is most commonly invoked from inetd as

          qmail-popup CHANGEME checkpassword qmail-pop3d Maildir

       with CHANGEME replaced by the fully qualified domain  name
       of the local host.

       qmail-popup  expects descriptor 0 to read from the network
       and descriptor 1 to write to  the  network.   It  reads  a
       username and password from descriptor 0 in POP's USER-PASS
       style or APOP style.  It invokes subprogram, with the same
       descriptors  0 and 1; descriptor 2 writing to the network;
       and descriptor 3 reading the username, a 0 byte, the pass-
       word, another 0 byte, an APOP timestamp derived from host-
       name, and a final 0 byte.  qmail-popup then waits for sub-
       program  to finish.  It prints an error message if subpro-
       gram crashes or exits nonzero.

       qmail-popup should be used only within a  secure  network.
       Otherwise  an  eavesdropper  can steal passwords.  Even if
       you use APOP, an active attacker can still take  over  the
       connection and wreak havoc.

       qmail-popup has a 20-minute idle timeout.

       qmail-popup is based on a program contributed by Russ Nel-
       son.

SEE ALSO

       maildir(5), qmail-alias(8), qmail-pop3d(8)