<snipped from the Vpopmail FAQ>
Then, every time someone pops in and authenticates, the follow happens:
1) vpopmail asks for an exclusive lock on the
~vpopmail/etc/open-smtp.lock file
2) it will wait for the lock, once it gets it, it will continue
3) it adds the pop users IP into ~vpopmail/etc/open-smtp file with a
time stamp. If the IP already exsists, it updates the timestamp.
4) it runs tcprules to regenerate the /etc/tcp.smtp.cdb file
5) releases lock and new IP becomes available to the next
smtp invocation.
At this point, the smtp server configured above will allow that
IP to relay for 1 hour (default).
You should setup cron to run the following:
40 * * * * /home/vpopmail/bin/clearopensmtp
Change /home/vpopmail to be your vpopmails home dir.
clearopenstmp will ask for a lock, clear out any roaming IP's
whos timestamps are over 1 hour old since last pop authentication.
merges the two files vpopmail does above and run tcprules.
Thus closing off relay for those aged IPs.
I think it's pretty cool :)
OK, based on this information I compiled Vpopmail with the
--enable-roaming-users=y. The /etc/tcp.smtp file does not exist but the
~vpopmail/etc/tcp.smtp file does so the configuration script automatically
selects the ~vpopmail/etc default location for the tcp.smtp and open-smtp
files. Now, this is where it gets a little messy. The ~vpopmail directory is
/usr/home/vpopmail. I have one file server and four mail servers. Each mail
server mounts it's /usr/home off the file server so all four mail servers
share the same ~vpopmail/etc/open-smtp and ~vpopmail/etc/tcp.smtp files.
The smtp invocation of tcpserver uses the -x ~vpopmail/etc/tcp.smtp
parameter to allow users who've pop or imap authenticated to send mail. It
works! In fact, it works pretty good and has been working, until recently
when a problem has surfaced and one that I believe is related to server
load. I think that the file locking code that checks for the file lock on
the open-smtp file is not actually honoring the lock file. If I sit and
watch the open-smtp file, it'll start growing away (as expected) and then
suddenly shrink back to nothing, and start growing again. I turned off the
clearopensmtp cron job and the behavior continued.
So, my theory is that now that my server is finally getting a decent amount
of traffic, whenever two auth requests come in at the same time, one is
reading in the file while it's still being written. I can't think of any
other reason the file would shrink. The last clue is that the open-smtp.lock
file gets created but it's date timestamp never changes. In fact, it's mod
date hasn't been updated since October. If I delete the file, another will
appear but it's timestamp remains the same as it's creation date.
Anyone encountered this? Anyone have a solution?
Matt
