Am 18.05.2014 00:22, schrieb Stan Hoeppner: > On 5/17/2014 6:14 AM, Charles Marcus wrote: > ... >> The reality is that the RFCs mandate that the null sender envelope >> address is one that must be accepted, as there are many things smtp >> that depend on it. > ... > > Spammers tried to take advantage of null sender handling en masse many > years ago and had little success with it. Receivers rejected the > messages by standard anti-spam mechanisms such as non existent PTR, > dnsbls, content filters, etc. And in fact some spammers still try to > use null sender today. Recent examples from Chinese IP space sending > spam to messages IDs scraped from mailing list archives, clearly a spam > bot infected PC: > >> Apr 29 22:32:52 greer postfix/smtpd[4968]: NOQUEUE: reject: RCPT from >> unknown[14.148.130.120]: 450 4.7.1 Client host rejected: cannot find your >> reverse hostname, [14.148.130.120]; from=<> >> to=<4d18f665.6090...@hardwarefreak.com> proto=ESMTP helo=<a01> >> Apr 29 22:32:52 greer postfix/smtpd[4967]: NOQUEUE: reject: RCPT from >> unknown[14.148.130.120]: 450 4.7.1 Client host rejected: cannot find your >> reverse hostname, [14.148.130.120]; from=<> >> to=<4d18f04d.3040...@hardwarefreak.com> proto=ESMTP helo=<a01> > > Check your mail logs and you'll likely find such rejections of null > sender as well. > > Certainly one should never reject mail based on the presence of the null > sender address, but by no means should anyone have a blanket accept > policy based on the mere existence of the null sender address
nobody said that - even not what you quoted above it only says you must not reject all messages based on the fact there is a null-sender in use and that is why using anything else than a null-sender for autoreplies and try to excuse that by clueless fools blocking all null-senders is only silly
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