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Re: email server



Paul Cartwright wrote:
On Sun December 13 2009, Joe wrote:
You can split the task of testing if you have the use of an external
Internet connection, possibly over ssh: you can connect to your own
server by IP address or by name using telnet. Apologies for the source
of this, but it's what I frequently quote to people needing to test mail
servers, and it seems accurate, just ignore references to Exchange:

  http://support.microsoft.com/kb/153119

tried to send you a test message, and got this back:
host mail.jretrading.com [80.177.211.93]: 550-sender IP address 72.52.240.41 is locally blacklisted here. If you think
    550 this is wrong, get in touch with postmaster

not sure if that is from my own fail2ban or my ISP... that IP isn't in my denyhosts file..

Sorry about that, it's my own blacklist. I've used the above email address openly for more than ten years... there cannot be a single email list on the planet that doesn't contain me at least once. In the last four complete days of logging, I've rejected over 10,000 bogus connection attempts, and yours today, of course.

I've compiled the list manually over the course of several years, an ISP getting the benefit of some doubt for a while. I can't honestly see any way of bringing pressure on ISPs to minimise the spam they send out other than by complaints of blacklisting from their paying customers. While Yahoo seems to have cleaned up its act quite a lot in the last year or so, many ISPs seem not to bother spam-checking their customers' outputs.

Had you, as a human, tried the suggested address, it would have reached me. I accept mail to it and abuse unconditionally, as required by RFC. No, not a single spam to either address for several domains over many years, despite the accepted wisdom on the subject. Possibly the spammers don't wish to attract the attention of the mail admin, who might be assumed to be a bit wiser and more resistant to scams than users...

More likely is that nearly all spam is now NDR spam, which shouldn't work if sent to the RFC addresses. Of course, it would in many cases. None of the ISPs seem to accept RFC address mail, and most companies who use POP3 collection have never heard the term 'RFC'.

In addition to the blacklist, I reject about twenty countries on HELO and PTR strings, a few really offensive ISPs by name (mostly German, oddly), and make an attempt to identify and reject 'generic' PTRs. Along with the Debian default of requiring complementary A and PTR records for the sending IP address and a HELO which resolves using public DNS, this cuts down the spam that exim4 accepts to between one and two a day, which Icedove normally spots easily. Without the blacklist, it's about forty a day.

--
Joe


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