Jasen Betts <[email protected]> wrote:- > Honest users will be sending through a smarthost, so probably an 'a' > in the 'by' clause unless they have some other arrangement with the > smarthost, or the smarthost has a broken by clause. > For this reason checking foreign received headers is a bad idea.
I check:- SMTP To - if it is not our domain or not a known user, it is refused. We don't send emails to ourselves either, so FROM = TO is refused too. SMTP sending IP's host name and whether it resolves to the sending IP address. HELO/EHLO and whether it resolves to the sending IP address. If the sending host name is on the hosts.amateur.spammers or hosts.professional.spammers lists it is rejected. > As received headers can trivially be forged, they are unsuited > to use in whitelisting. Don't examine the Received headers. Seldom use whitelisting. > > Because mail admins, like me for example, are unhappy at the vast > > amount of spam originating from ranges of dynamic IP addresses. > > After a while, we block hosts like > You could just do what bt-internet does, and blacklist everyone, and > only whitelist on request, but that may require additional staff.... BT often can't give a valid EHLO and when they do, it usually relates to the wrong IP address. There are two types of BT (British Telecommunications) Internet - resale and wholesale. Wholesale is generally good. Retail is crap so I avoided all the time from about 1992. BT retail Internet is just like Windoze - ugh ! The installation branch of BT, Openreach, has poor organisation. It will be legally separated from BT (floated-off). Our existing Exim defences function well. The whole system is so reliable that little effort is required to enjoy a virtually spam-free environment. -- Regards, Paul. England, EU. England's place is in the European Union. -- ## List details at https://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
