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SPAM Blocklists (DNSBL/RBL) and How They Affect Salesforce Email Delivery

Дата публикации: Jul 23, 2026
Описание

A DNSBL (Domain Name Service Block List) or RBL (Real-time Block List) is a list of Internet Protocol (IP) addresses published via the Domain Name System (DNS). These lists are used by email administrators and receiving MTAs (Mail Transfer Agents, i.e., email servers) to block the delivery of email from flagged IP addresses. The goal is to mitigate mail abuse from spammers and phishers.
ESPs (Email Service Providers) like Salesforce work proactively with major blocklist providers to ensure that legitimate Salesforce IP addresses remain de-listed and email delivery rates remain high.

How Blocklists Work

Blocklist providers have their own proprietary methods for determining which IP addresses to add and remove from their lists. There are no universal standards governing how blocklist providers operate. In most cases, major reputable blocklist providers (such as Spamhaus) work cooperatively with ESPs to de-list legitimate IP addresses. However, some minor providers do not accept de-listing requests or charge a fee for removal.
Salesforce works with major blocklist providers to ensure the highest deliverability of email sent from Salesforce MTAs.

Решение

Salesforce's Approach to Blocklists

Salesforce actively works with reputable blocklist providers to maintain de-listed status for Salesforce IP addresses. Email administrators and email providers should research and use major, reputable blocklist providers that cooperate with ESPs on de-listing. Providers that refuse to work with ESPs for de-listing, or that charge a monetary fee for removal, are generally not suitable for enterprise production use.
Salesforce has encountered minor blocklist providers such as UCEPROTECT and SORBS that have not been receptive to working with ESPs. Salesforce cannot control which blocklist services a recipient's mail server uses — Salesforce can only recommend that the mail provider use a reputable service.

How to Investigate an RBL Block

If Salesforce email appears to be blocked due to an RBL listing or flagged as spam, Salesforce Support can investigate if you provide one of the following:

  • Email log lines from Salesforce: Navigate to Setup, search for Email Log Files, and create a log request that covers the timeframe of the blocked email.
  • A copy of the blocked email with full headers: The headers will show the RBL reference or spam flag.

Salesforce cannot investigate specific RBL activity without log evidence or email examples that illustrate the issue.

Номер статьи базы знаний

000387311

 
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Salesforce Help | Article