We too have a problem with:
- some users checking mail too frequently
- some users leaving large amounts of mail on the server
- compounded with some few users who do both!
Running qpopper 4.0.3, using inetd, linux and peaking at around 100 pop sessions
per minute (24 hour average is around 30 per minute).
Although the point made about qpopper's server mode lessening problems caused by
large maiboxes is good (in fact this was a great improvement for us), there is
still a considerable extra load on the server caused by leaving large amounts of
mail on the server. One problem is that users make frequent failed attempts to
download the mail - not grasping the fact that some patience is required. It also
seems to me that qpopper will still have to 'index' the mailbox each time it is
accessed and calculate uidl's (someone correct me if I'm wrong in this).
In order to provide a *fair* and workable mail service for all, we have implemented
two 'policing' systems:
1. The poplog is periodically checked and users who are checking mail at, say
more than 10 times in 10 minutes are added to qpopper's 'nonauth' file and
thus prevented from acessing mail for, say a 30 minute period
2. All mailboxes are checked in the early hours of the morning and any exceeding
a specified size limit (eg. 10Mb) are prevented from receiving additional mail
as well as added to the qpopper 'nonauth' file - this time they cannot be removed
except by a manual process (eg. if the user calls the helpdesk the problem is
explained and the blocks are removed).
Both systems are fully automated (via scripts run from crontab) and exceptions are
allowed (for example some corporate customers using fetchmail to distribute mail
to users whose mailbox can grow very large).
If anything implementing this policy has slightly increased the workload on our
helpdesk, however most users (we are a dial-up isp) are unable or unwilling to download
large mailboxes so would have called the helpdesk anyway and the frequent poppers
(some of whom are constantly getting 'blocked') were not responding to other, less
drastic measures.
The only thing I can't be sure of is that these measures have actually reduced server
load or improved server performance :-;
The point made in the original post re notifying users of the problem is a good one and
we should do this (obviously pointless for the large mailboxes).
If anyone else has ideas or experience I would be interested to hear them...
Regards, Peter
Netlink Connect, Australia
>
> I'm dealing with the next order of magnitude of users, many checking every
> minute. We're logging 150-200 pop sessions/minute. However, this frequent
> checking (especially with LMOS) is more of an annoyance to ME than
> affecting anyone.
>
> I've considered modifying the qpopper source to keep the connection open
> for x minutes after the customer closes the session. I'd also change the
> pop lock error message to explain it (instead of the POP lock
> busy). However, any changes to customers will just get them calling in,
> regardless of how well I explain things in the error message. My poor tech
> support reps will be tied up:
>
> 1) explaining why they can't check mail "like the always have"
> 2) justifying our policy to the people who understand it
> 3) spend x minutes waiting for pop sessions to time out after the customer
> attempts to check mail
>
>
> - SteveP
>
> At 03:24 PM 4/16/2002 -0400, you wrote:
> >Hello all,
> >
> >I was just wondering if anyone knew of a commonly used program used in
> >conjunction with Qpopper, or perhaps even a widely used patch, that would
> >enable me to limit the frequency with which users check their
> >mail. Currently there is no such limit, and believe it or not many have
> >their Eudora setup to autocheck every minute. This is unacceptable with
> >almost 2000 users per machine. Especially considering that they regularly
> >keep messages on server as well for a period of at least 5 days. I know
> >that I've seen other institutions implement such restrictions, and you are
> >sent an error message via standard POP protocol it appears, which Eudora
> >displays in the status telling you you are checking mail too often. THis
> >is more than sufficient. Any help or recommendations would be GREATLY
> >appreciated. Thanks in advance.
> >
> >PS - The client getting the descriptive error message is by FAR the most
> >important thing, as to avoid unnecessary calls to our helpdesk people.
> >
> >---
> >Tim Meader
> >ACS Government Services, Inc. - (301) 286-8013
> >[EMAIL PROTECTED]
>
>
