That is because you do not see in the header FROM as was set during mail
transmission (when one mail server connects to another before initiating
data transmission it sends out FROM (sender) and RCPT (recepient) commands.
Some email servers will keep this around and consider spam any email where
during transmission FROM is not equivalent to "From" header. Such software
is hotmail for example. Because many mailing lists (quite appropriatly)
set FROM during transmission to their own, these get classified as SPAM
and mailing lists have to be whitelisted. If RMX or RTDNSBL are implemented,
thse mail filters (checking FROM in transmission and "From" in header)
have to be implemented as much as RTDNSBL because otherwise spammers would
just begin to set absolutly different FROM during transmission to domain
that does not have RMX and still use their preferred forgery domain in "From"
header which will make you think email came from that domain and send spam
report to them. Now as I mention those mailing lists that actually set
FROM during transmission to actual sender (taking it from "From" header)
are all also have to be whitelisted bacause otherwise RMX software would
think email is being forged because sender mailing list is not authorized
to send email for this domain. In the end no matter what we do ALL mailing
lists have to be whitelisted for RMX or RTDNSBL.
This matter has been discussed before and everybody agreed that all of
the various RMX proposals break mailinglists and that they would have to
be whitelisted. Some pointed out that those using hotmail already
whitelist mailing lists on regular basis and do it on per-user level - but
that is because email is classified by HOTMAIL as either spam or not and
their email servers do not answer with 500 but just based either send
email to regular folder or spam folder for each user, allowing filters to
be implimented on per-user level. Current DNSBL and RMX proposals actually
do send 500 answer during email transmission, which means whitelisting of
mailing lists have to be done on per-mailserver basis and this is a
problem for ISPs.
I hope I explained this all correctly and fully so everybody can understand,
this has been discussed before and no solution has been given yet that would
not allow for spammer to also use the same solution to get around the filters.
In my opinion until somebody tells me how to deal with mailing list problem
RMX should not be implemented, if we do have a solution, then sure - RMX
or RTDNSBL can be done - it'll not stop spam but just limit forgeries to
different domains, but nothing bad would happen from it then and if there
is some good, then why not do it.
On Fri, 7 Mar 2003, Gary Feldman wrote:
From: asrg-admin(_at_)ietf(_dot_)org
[mailto:asrg-admin(_at_)ietf(_dot_)org] On
Behalf Of william(_at_)elan(_dot_)net
Sent: Thursday, March 06, 2003 11:53 PM
...
Ok, you're right - ietf are good with technology and set FROM
in the mail
transmission to mailing list (which actually causes some spam
filters to
think email is forged), but there are mail lists and
forwarding systems
that do not do this and set FROM to the original sender.
I think this is backwards. The mail headers I see from this
mailing list keep From: set to the original sender, and add
a Sender: field identifying asrg-admin as the true sender.
MS Outlook 2002, for what it's worth, reasonably interprets
these fields to combine them with the "on behalf of"
verbiage illustrated above.
Gary
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