List Spam Filtering
freebsd-questions at herveybayaustralia.com.au
Wed May 15 02:23:50 UTC 2013
On 05/12/13 22:04, Rich Kulawiec wrote:
> 1. Restricting mailing lists to "subscribers only" has been a best
> practice since the last century. It's a very good anti-spam tactic.
> 2. However, doing so -- for a list run via Mailman, like this one --
> does not pose a significant impediment for non-subscribers. By default,
> Mailman will hold traffic from non-subscribers for list-owner approval.
> Provided the list-owners check that queue periodically and have reasonable
> spam-spotting abilities, this works beautifully.
> 3. Note that Mailman, as part of that same mechanism, allows list-owners
> to add non-subscribers to a list of those permitted to send traffic to
> the list without approval. This feature is probably more often used to
> allow traffic from alternative addresses for subscribers, e.g., someone
> is subscribed as fred at example.com but sends occasionally from fred at example.net.
> But it can just as easily be used for non-subscribers if the list-owners
> so choose.
> 4. List-owners may also find it useful to keep track of which spammers
> repeatedly attempt to abuse the list and block them at the MTA -- which
> has the desirable side effect of blocking them from ALL lists. I do this
> on a user/host/domain/network basis, and it's proven itself to be worth
> the effort.
> So: setting the "subscribers-only" flag on Mailman has major advantages,
> at the cost of additional work on the part of list-owners -- which can
> be mitigated in part across all lists by making changes to the MTA.
I'm a big fan of _not_ having to subscribe to a list to get a quick hand
with a one off problem (obviously not this one!)- otherwise too many
lists get subscribed to, oodles of messages come in which you can't do
anything about and so forth (so its not simply just a matter of
subscribe, unsubscribe as noted). Unfortunately, many see it as a spam
filter and thereby abuse it. How often do you need help with an issue
with libreoffice, mozilla whatever, or other application? And yet
subscription is compulsory and a ton of messages (devs convs mostly)
come flooding in within minutes.
Aside from all that, the last suggestion (4) should be possible using
some simple filtering without the need to change the subscription
parameters. It could be possible to even do it automatically saving
further work on a list-owner.
I admit the spam is getting worse, but there are still many more users
sending who would like try before they buy - or subscribe. FreeBSD is an
OS, yes, but it does give users options and freedom; and although many
are willing to give up their freedom because it is *appears* safer, they
tend to have serious regrets in the light of day. Better to find a way
to maintain the freedom (and minimise the overheads required for
oversight) through other measures.
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