Re: lost messages

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From: Katharine Thayer (kthayer@pacifier.com)
Date: 02/23/03-03:24:34 AM Z


Hi Gordon,
Here's what my ISP says about SpamCop blocking some of my list mail:

They say SpamCop is one of several spam-filter services they subscribe
to and they consider it one of the best, and would not consider not
using the service.

They say the only thing that can be done about my problem is for the
University of Saskatchewan to get themselves off the blacklist by
satisfactorily explaining the circumstances that got them on the
blacklist in the first place (such as a server left open so a spammer
could use it as a sending server) to the SpamCop folks.

When I asked why I get some of the mail from usask; it's not blocked
every time, he said it must be because the university routes their mail
through several servers, and only one of them has been blacklisted. So
the mail that goes out through that "bad" server is blocked, but the
mail that goes through a different server, that hasn't been blacklisted,
is not filtered out.
Katharine

 

Gordon J. Holtslander wrote:
>
> Hi:
>
> A critique of spamcop os here: http://jhoward.fastmail.fm/spamcop.html
>
> Everything thats wrong with spamcop ...
>
> SpamCop is using the 1st style of filtering. It blocking messages because
> they are coming from a particular computer. It does not read the message
> to check for spam content
>
> SpamCop uses a blacklist - It will reject message from any computer on the
> blacklist.
>
> A computer can be added to the blacklist by someone reporting to have
> recieved spam from this computer.
>
> If there is a recent report of spam from a computer it will be
> blacklisted. After a while, if there are no complaints the computer will
> be unblacklisted.
>
> So if sask.usask.ca is currently on the blacklist Katherine's email from
> the list gets tossed in the garbage. When it comes off the list she gets
> email, but she will NEVER recieve the email that was sent while
> sask.usask.ca is blacklisted
>
> This also depends on the ISP maintaining updated information - likely
> needs to be updated every 4 hours.
>
> The problem is that occasionally valid email gets reported as spam
>
> Quoting above site:
>
> -----------
>
> A SpamCop report occurs when a SpamCop notification system user reports a
> message as spam, and SpamCop's analysis results in it being connected with
> a particular email server. At FastMail.FM we have seen the following
> result in SpamCop reports
>
> Genuine spam is correctly connected with the correct sending server.
>
> Genuine spam is received by a user, who forwards it to another email
> provider (e.g. due to an automatic rule they have set up) or moves it with
> their email client manually, and is then reported from the final location.
> This can result in their own email provider getting listed because that
> looks like the "spam source", because that is the server through which it
> was forwarded.
>
> A virus results in an email being sent, which is incorrectly reported as
> spam.
>
> A SpamCop notification user sends someone a message which the recipient
> bounces (e.g. they are rejecting emails from that sender automatically),
> and the SpamCop user reports the bounce notification.
>
> -------------
>
> >From the error message posted on spamcops site it appears that someone was
> forwarded, or recieved through a virus, spam that had originally been sent
> to a sask.usask.ca address. They filed a spamcop report on this,
> resulting in sask.usask.ca being blacklisted.
>
> This means that any ISP using SpamCop will toss all list messages in the
> garbage when this occurs.
>
> Its up to list suscribers to deal with their ISP's about this. I can't do
> anything about it.
>
> Gord
>
> On Fri, 21 Feb 2003, Eric Maquiling wrote:
>
> > On 02/21 10:05, Katharine Thayer wrote:
> > > On the other hand, an ISP-level filter that blocks messages with the
> > > subject line "Aqua Regia" might at some times be a useful feature.
> >
> > Sorry for being REALLY OT here but 2 things can happen at the ISP
> > level. Think of them as 2 doors:
> >
> > 1st door
> > email comes in
> > email servers ask "what IP address did you come from?"
> > email server looks up the IP address
> > lookup says "that IP address routinely sends SPAM"
> > email server closes the door on that email
> > next mail
> > lookup says "that IP address is good"
> > email server forwards the mail to:
> > 2nd door
> > another serivce
> > checks for the entire email for anything that might be
> > considered as spam
> > checks good
> > email goes to recipeient
> > checks bad, words like "click here now!" or "increase your ***"
> > email gets rejected.
> >
> > This concludes our basic email server lesson for today.
> >
> > (Thought I might contribute to something I actually know something
> > about)
> >
> > You guys are super cool printmakers.
> >
> > --
> > Eric
> >
>
> ---------------------------------------------------------
> Gordon J. Holtslander Dept. of Biology
> holtsg@duke.usask.ca 112 Science Place
> http://duke.usask.ca/~holtsg University of Saskatchewan
> Tel (306) 966-4433 Saskatoon, Saskatchewan
> Fax (306) 966-4461 Canada S7N 5E2
> ---------------------------------------------------------


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