> Just for the sake of argument, is everyone seeing that below in their
> message traffic?
>> To: port-vax@netbsd.org
>> Subject: Re: Returned mail: see transcript for details
...
>> Your mail to efmiwg7@bcs.org.uk was caught by the
>> SpamAssassin filter running on the bcs.org.uk mail system.
>> 
>> To confirm that your mail is genuine, please click this
>> link, or paste it into your browser:
>> https://bcsnet.bcs.org.uk/approve.php?c=6b918fd45057059bc6c2649

Yes.  That was sent to the list, so everyone on the list got it.

It's a broken challenge/response system, probably autoresponding to
malware-forged email (since no legitimate mail ever comes from
port-vax@netbsd.org).

I tried to write to the postmaster at the offending site, but that
fails too; their mail system is apparently broken in more respects than
just using challenge/response spamware.

The simplest thing is just for someone to follow that link; it's the
easiest way to shut up their bugware (and perhaps teach them something
about when challenge/response systems are inappropriate).  I'd do it
myself except that it's https: and I have no https: support.

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