Solve an email block (RBL)

This guide presents the operation of the LBRs, the questionable policy of some of them and the means to resolve a possible email blockage.

Preamble

• The RBL (Realtime Blackhole List) or DNSBL (Black List DNS) are lists containing addresses / IP / names of suppliers / servers, known as large spam transmitters.
• These are often large, generalised blacklists (blacklists), which can be used to identify messages that are considered undesirable and those that send them, which some providers maintain (smtpcheck, uceprotect: non-exhaustive list)…

Adding email address to RBL

When an email address is identified as belonging to an undesirable sender, it is blocked to prevent the receipt of unsolicited mail. A blockage in the RBL does not expire. Addresses will be listed indefinitely.

If you receive a message that your email address is blocked by RBL, this means that the Infomaniak security system has detected suspicious or undesirable activities associated with this email address. This may include mass sending of unsolicited mail, participation in phishing campaigns or other malicious behaviors.

Solve an email block (RBL)...

... if the error mentions your address and RBL

If you get type errors

anna.a@domain.xyz is rbl blacklisted - http://chk.me/rbl

when sending an e-mail and you think it's a false positive, contact Infomaniak support.

To prevent your email address from being blocked by the RBL blocking system in the future, follow the best practices of using email:

1. Don't send unsolicited mail or mass message to unknown recipients.
2. Sort regularly the recipient list used.
3. Do not participate in phishing or cybercrime activities.
4. Make sure you have the best level of security where your e-mails are used:
   1. strong password
   2. up-to-date software
   3. operating system (iOS, Android, Windows, macOS, etc.) up-to-date
   4. configuration of the associated domain up-to-date

... if the error mentions an organism like Sorbs or Barracuda

If you get type errors

554 5.7.1 Client host blocked using sorbs

or similar:

1. Follow the procedure of the organization mentioned (e.g. http://www.barracudacentral.org) to get your address deleted from the list.
2. Temporarily change your Internet access provider or connection method - WIFI vs 4G/5G - to send your messages.
3. Inform your correspondent and their mail provider to do the necessary and/or no longer use an unreliable LBR.
4. Wait a few hours and try again.

Less and less professionals (ISP, hosting companies, etc.) use standard providers Backscatterer / UCEPROTECT and there are a lot of other very effective lists, such as ABUSIX or SPAMCOP, well-maintained and whose real purpose is to fight spam, one of the priorities of Infomaniak.