The 03.03.23 at 14:46, Theo v. Werkhoven wrote:
I have a few different mail accounts, from different ISPs. The smtp host of any of them rejects mail with the "from" of another provider - correctly, of course -. The only way left for us is to use our local sendmail or postfix to handle the delivery.
If you are going to say that I could set up different relay host depending on the "from", it wouldn't work the moment the provider notices the IP is from the "other" provider.
There is such a thing as pop-before-smtp, which normally allows you to use an ISPs mail server as long as you supply your authentication by popping first.
Yes... suppossing that my ISPs use it, and that it would be possible to coordinate fetchmail and postfix, which I think it's not possible. At least one of my provider requires password; and I would have to configure postfix to somehow send each mail to a different relay depending on the from. One more reason not use the ISPs' relay: often they fail to send, and don't inform me. Ie, they fail silently. Mass ISP are not... let's say, very "helpfull". For example, they do not respond to email enquiries, I have to phone a 906 number (something less than 1 eur per minute) if I have a problem.
Instead, you could check whether the "from" domain is real, or use white lists.
Or spamassasin, that seems to catch most of the spam.
I'm already using just about every measure you can think of, dynablocking is/was (I disabled it to test) just one link in the chain.
I can very well understand that... -- Cheers, Carlos Robinson