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If Legitimate Mail is Blocked

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Updated information at: Classic Linux.

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Our SMTP filtering does not block spam per se. It blocks all mail arriving from certain hosts and IP addresses that are more likely than others to send spam. Non-spam mail coming from these locations will also be blocked. Although the fraction of legitimate mail that will be blocked is small, it is not zero.

If a correspondent is unable to send you email because our SMTP filtering is blocking his host or IP address, here are some of your choices.

  • You can ask the person who administers the sending site to correct the problem that is causing the blocking, if it is correctable. For example, if he is sending mail from a dynamic IP address, he could relay mail via his connectivity provider's mail server. If he is sending mail from a host that does not have valid DNS, he could attempt to correct the DNS configuration, or relay outgoing mail via another server (a “smarthost”) that does have valid DNS. If he is operating or sending from a pro-spam site that is blocked because of its reputation, he can persuade his organization to cease its pro-spam activities and have itself de-listed from the various black lists.
  • You can ask the sender to get a different mailbox (for example, at a free email provider) and send you mail from there.
  • You can switch off your own SMTP filtering. Then you will be able to receive mail from this sender. You will also get more spam. Details are on the page smtp_filtering_to_keep_out_spam. (Note: switching off SMTP filtering does not leave you completely helpless. All incoming email is also scanned by spamassassin_to_identify_spam and you may adjust your .procmailrc script to delete or refile spam as appropriate to your needs. This may, however, increase the burden on you to visually check your spam folder for any misfiled mail.)
  • You can add an alternate email address for yourself, keep SMTP filtering switched off for this alternate address, and ask the sender to send you mail at this alternate email address. Details are on the page Selective Whitelisting.

If you think that our blocking is too aggressive, and that some innocent party sending mail from a well-administered location, not affiliated with any pro-spam organization, having valid DNS, and not using a dynamic IP address, is being unfairly blocked, then please do the following.

FIRST, take action as described above, so the innocent sender is able to send you mail.

THEN, ask the person who administers the sending site to go to one or more of the web sites below, and check to see if his IP address is being blocked in any black lists, and if so, to take all possible reasonable steps to get his IP addresses delisted from the ones that are in wider use.

FINALLY, please contact and notify us of the situation.

classic/if_legitimate_mail_is_blocked.txt · Last modified: 2021/01/30 04:53 by admin