> Your saying that it's your ISP, but I can't even say that,
> unless our ISP is filtering mail destined for our mailserver.
> Because, the messages are supposed to be sent to my company's
> mailserver and Yahoo Groups is whitelisted on our server, yet
> my messages get bounced on a regular basis(lately every 2-3
> days) and those that get bounced don't even make it to our
> server.

I've spoken with my ISP. They use SpamAssassin which uses the
SpamCop blacklists. This is confirmed by the bounce history
messages you can see when you look in yahoogroups.

The thing that gets confusing is that not everything from
yahoogroups gets bounced. For example I am receiving the stuff
from firebird-general at the moment (hence I got to see your
message). AFAICT this must be because yahoogroups sends from
more than one server - with some groups tending to send from
one particular server, and some from another. SpamCop blocks
by ip-address so sometimes only one of the yahoogroups servers
is "down".

I discussed trying to get yahoogroups whitelisted with my ISP.
Apparently (courtesy of less controlled groups than ours) there
is a large amount of spam traffic coming out of yahoogroups.
So the ISP does not want to whitelist for everyone and to try
and whitelist just for my domain is apparently difficult. I
was given an option of using my own mail server, but I need to
update my gateway box and currently dont have the time or
money to set this up.

> I think some ISPs might be taking it a step too far for spam
> filtering.

Perhaps. Although I must say that ISPs who perform spam and
virus filtering (as mine does) are probably of large benefit
to the internet at large. Given that the large majority of
internet users are operating without the knowledge to deal
with these issues effectively, and even those of us with the
knowledge have better ways to spend out time, it seems only
correct and appropriate that ISPs provide this service.

I would prefer to see the problem dealt with between SpamCop
and YahooGroups (and any others that have this problem). It
seems to me that a cooperative approach could benefit all.

Indeed if more ISPs did such filtering the pressure would be
on all other services (such as YahooGroups) to try and deal
with the problem more effectively. And this is where the
pressure should be applied. Stop trying to place it on ill
prepared end-users - have organisations with the resources
and knowledge find ways to improve the situation.

--
Geoff Worboys
Telesis Computing