Hi Gary,

DRAC is cool!  It handles the network and entry timeout issues for me, and
I wanted it to go just a little futher, so...

Here is a tiny hack I cobbled together so that I could use DRAC with
Courier-IMAP without modifying any Courier source code.  Instead, you just add
it after authdaemond in AUTHMODULES in the courier pop3/imap config files.

For my basic config, I have Postfix and Courier-IMAP running on multiple
boxes behind an OpenBSD load-balancing firewall.  When a user checks mail
with IMAP/POP3, there's no guarantee that they are going to hit the same server
again with SMTP.  All servers run SMTP and IMAP/POP3.  All servers must
be able to allow users who authenticated with IMAP/POP3 on any other
server to send SMTP mail.  So here's what I did:

Each SMTP server runs DRAC.  Simple enough...Postfix points to dracd.db with
smtpd_recipient_restrictions = ... check_client_access btree:/etc/mail/dracd, ...

Each POP3/IMAP server calls this little program after authentication.  This
program grabs the client's IP address from environment variables.  Then, it
connects to each DRAC host and enters it.  Simple enough....

/*
 * This little utility is based off of code found in a DRAC popper patch
 * and a few lines of Bruce Guenter's relay-ctrl-allow utility.
 *
 * http://mail.cc.umanitoba.ca/drac/pop.html
 * http://untroubled.org/relay-ctrl/
 *
 * To configure:
 *
 * See main() for the list of DRAC servers to register with.  Change
 * accordingly.  
 *
 * To compile: cc -o drac-add drac-add.c -L/path/to/drac -ldrac
 *
 * To use:
 *
 * Figure out where your Courier configuration and authlib directories are at.
 * My sample values are for Courier as installed from the OpenBSD ports tree.
 *
 * Copy drac-add to /usr/local/libexec/authlib/
 * Edit /etc/courier-imap/pop3d and add drac-add to the end of AUTHMODULES
 * Edit /etc/courier-imap/imapd and add drac-add to the end of AUTHMODULES
 * Restart imapd and pop3d
 *
 * Chris Cappuccio - chris@nmedia.net
 */

#include <stdio.h>
#include <stdlib.h>
#include <syslog.h>
#include <string.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <unistd.h>
#include <errno.h>

void drac_update_host(char *drachost) {
	char	*err;
	struct in6_addr ip6;
	struct in_addr  ip4;

#ifdef DEBUG
	syslog(LOG_INFO,"drac_update() called: drachost=%s user=%s",drachost,getenv("TCPREMOTEIP"));
#endif

	if (inet_pton(AF_INET, getenv("TCPREMOTEIP"), &ip4) == 1) {
		if (dracauth(drachost, ip4.s_addr, &err) != 0)
			syslog(LOG_ALERT,"dracauth() Error \"%s\" for"
			" user %s",err,getenv("TCPREMOTEIP"));
	} else if (inet_pton(AF_INET6, getenv("TCPREMOTEIP"), &ip6) == 1) {
		if (IN6_IS_ADDR_V4MAPPED(&ip6)) {
#ifdef __OpenBSD__
			ip4.s_addr=ip6.__u6_addr.__u6_addr32[3];
#else
			ip4.s_addr=ip6.s6_addr32[3];
#endif
			if (dracauth(drachost, ip4.s_addr, &err) != 0)
				syslog(LOG_ALERT,"dracauth() Error \"%s\" for"
				" user %s",err,getenv("TCPREMOTEIP"));
		} else {
			syslog(LOG_NOTICE,"drac_update() doesn't support IPv6"
			" yet.");
		}
	} else {
		syslog(LOG_ALERT, "drac_update inet_pton failure! drachost=%s"
		" user=%s errno=%i",drachost,getenv("TCPREMOTEIP"),errno);
	}

	return;
}

int main(int argc, char* argv[])
{
  if (getenv("TCPREMOTEIP") == NULL)
    err(111, "No TCPREMOTEIP found");

  if (getenv("AUTHUSER") && getenv("AUTHARGV0") && getenv("AUTHENTICATED")) {
    /* if success then courier is happy, so we update our DRAC hosts */
    drac_update_host("172.16.100.10"); /* CHANGE DRAC SERVER(S) HERE */
    drac_update_host("172.16.100.11");
  } else
    syslog(LOG_NOTICE, "drac-add called without AUTHUSER"
    "/AUTHARGV0/AUTHENTICATED!");

  /* Courier-IMAP Magic from relay-ctrl-allow */
  if (argc > 1) {
    execvp(argv[1], argv+1);
    return 111;
  }
  return 0;
}