Try entering from the command line and also adding to /etc/rc.d/rc.local:
echo "5" > /proc/sys/net/ipv4/tcp_retries2
The Linux default value is 15 I think. This will speed up the release of the mailbox lock by reducing the number of times the OS retries the TCP connection before giving up on it. If you reduce it much below 5 you risk dropping connections that are experiencing packet loss, so this is a tradeoff.
This should only happen to customers who are on dialup links that drop unintentionally, or who get impatient and disconnect from the Internet without closing out the POP3 session, or who have misbehaving antivirus software.
The only other fix I know of, other than reducing the number of TCP retries, is to put the problem users on webmail which will always finish the POP3 session gracefully even if the web client disconnects.
Is there a quick way to unlock a users mailbox after a failed pickup of emails? Currently, we have to tell our users if this happens they must wait approximately 20 mins for the mailbox to unlock itself and some are finding this unacceptable.
We are running qpopper 4.05 on redhat9. It is also run in server mode.
