CONTENTS
========
Summary
Background
Bounce handling
Digests - some problems
The new archive - notes and tips
SUMMARY
=======
This is the first of several update posts concerning the recent changes to
UKTC. The way in which bounced (undelivered) messages are dealt with under
the
new system is outlined, along with a note about digest delivery and the new
archive.
BACKGROUND
==========
On 12 December 2001 I announced that plans to move the UKTC onto a new
machine
using different software had been brought forward and implemented in a hurry
due to the rapidly worsening state of the old machine.
That announcement itself was sent out in a hurry and as a result did not
cover
all the consequences of the recent changes. As I don't have time to compose
an
all embracing document on the changes at present I'll be posting information
in
dribs and drabs with a subject line beginning "UPDATE:"
BOUNCE HANDLING
===============
The UKTC handles an average of over 50 messages per week for over 250
subscribers - over 12500 message deliveries each week. The vagaries of the
Internet inevitably mean that not all of those messages reach their
destination. Those that don't are 'bounced' - returned to the sender. In a
mailing list context the sender is not the original author of the message,
but
the list's administrator.
Many mailing lists automatically delete subscribers whose messages are
returned. The assumption is that the address is no longer valid and it is
therefore pointless to continue sending messages to it.
Until the recent changes I had chosen to be somewhat forgiving about messages
that didn't reach their desination and were bounced back to me, painstakingly
reading through them and noting persistant offenders. Occasionally I've
manually removed subscribers if mail has carried on bouncing and looks as if
it
is a problem that won't be resolved, using the kind of fairly fuzzy criteria
that humans are much better at assessing than computers.
The amount of work involved in this has grown considerably as the UKTC has
grown. Accordingly I have now decided to make use of features for automating
the handling of bounces.
Subscribers whose messages bounce will now be removed from the list
automatically. Removal will not take place at the first bounce - if it did,
everyone working for a local authority, together with all users of lineone,
yahoo, hotmail, appleonline and freeserve would have been removed by now!
Instead, thresholds have been set which I hope will ensure that subscribers
experiencing temporary mail problems will not be unduly kicked off, whilst
addresses that really have had it will go. At present the thresholds are 20
fatal or 50 transient bounces in any 10 day period.
Should you find yourself unexpectadly unsubscribed this is likely to be the
reason why. An attempt will be made to notify anyone who is unsubscribed in
this way, but naturally this is unlikely to succeed since the reason for the
action is that their mail is not getting through.
There are certain people who may be more affected by this than others. The
two
main groups that come to mind are:
* Those who have a quota on their mail account. If you don't check your
mail
for a while (perhaps because you're on holiday) and go over quota new
mail
for you will be refused. This will result in bounces being generated.
Different systems differ in the type of bounce generated for over quota
accounts - some use transient codes whilst others use permanant ones. If
you
are going on holiday you should consider marking your UKTC subscription as
'VACATION' using the accoung management facilities at
http://listcontrol.oak-wood.co.uk/uktc/
* Those using work email accounts where particular corporate security
policies exists about attachments. A number of local authorities are
included here. These authorities quarantine attachments but send a message
to the return address of the mail envelope advising the sender that the
message has been quarantined. These messages are likely to interprated as
bounces. Whilst it is very rare for 20 attachments to be sent to the UKTC
in 10 days, it's not impossible and if you work for such an employer you
should bare this possibility in mind if your subscription suddenly stops.
DIGESTS - SOME PROBLEMS
=======================
Digest readers may have noticed that arrival of digests is rather sporadic at
the moment. This is due to an odd problem affecting the UKTC whereby certain
scheduled tasks are not happening.
I am looking into this, but in the mean time I have implemented a work
around.
Digests are currently being generated whenever a new message is sent to the
UKTC and more than 24 hours have elapsed since the last digest was sent.
It is hoped to be able to return to daily digest mailing at a set time as
soon
as possible.
THE NEW ARCHIVE - NOTES AND TIPS
================================
The following are a few notes on the new archive available at
http://listcontrol.oak-wood.co.uk/uktc/archive.
The archive now covers all the messages that have been sent through the UKTC
in
the three years since it's inception - that's around 6000 messages. In order
to
make the whole thing a bit more manageable it has been broken down into one
year segments.
For each year four indexes are available - by thread (the default), date,
author and subject. The first two of these are ordered with the most recent
message first.
From any given message you can move to that message's position in any of the
four indexes for the year by clicking the appropriate link in that message.
This is a slightly slow process as the correct position has to be calculated
on
the fly. By this means once you've found one message from Mr X you can find
all
the other messages from that year by the same Mr X by clicking on the
link 'Author Index'.
There is also a dedicated archive search facility. The archive front page has
a
form to access this, or you can find one in the dark blue navigation bar down
the right of any archive page.
The archive lags slightly behind the list. In order to avoid overloading
things
messages are not added as they arrive. Instead, the archive is updated every
30
minutes. The search index is updated every night in the small hours, UK time.
--
Chris Hastie
Administrator
The UK Tree Care Mailing List
http://uktc.oak-wood.co.uk/
--
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