Start with the exact result
In a rejection notice, preserve the receiving server's complete SMTP response, including any provider name, list name, DNS zone, or lookup URL. A short status code or a generic phrase such as “blocked” may not identify who made the decision. If the report is vague, ask the recipient's mail administrator or your sending provider which source was consulted and which sending identifier was evaluated.
Match the lookup to the affected identifier. A receiver may evaluate an outbound IP, a domain, or another item named in its diagnostic. Compare the same value shown in the receiver's response with the relevant row in a provider-level check; a domain result does not answer whether an IP is listed, and vice versa. ReputaPilot’s guide to provider blocklist results explains how to read listed, clear, and unresolved rows.
Keep a short case note with the time, sending identifier, receiving system, exact rejection text, and named operator or list. Avoid including recipient personal data when sharing diagnostics with a provider.
Check provider-level blocklist results →General preparation for any operator
Before contacting an operator, confirm the result against its own lookup page and investigate the sending system that produced it. Review recent sending activity, account access, list quality, authentication, and the mail route involved. Resolve the underlying issue where you can, then follow the operator's stated request method and provide the information it asks for.
Check who controls the affected IP or domain. If an email service, hosting company, or ISP owns the sending IP, involve that provider when the operator's policy requires the network owner to act. Keep the provider's case reference and recheck the same identifier and list after the operator responds.
These are preparation steps, not a universal delisting policy. Operators use different listing criteria and request paths, and a request does not guarantee removal.
Provider-specific guidance
Use the current official page for the provider named in your result. The details below describe only the paths documented by these operators; they are not interchangeable instructions for other lists.
Spamhaus
Search the affected IP address or domain in the Spamhaus IP and Domain Reputation Checker. Read which Spamhaus data set is named and follow the instructions shown for that result. Spamhaus's general removal guidance says to use the Checker and its ticketing process; requests through other channels are not handled. The request must come from the registered owner of the IP or domain. If that is not you, Spamhaus directs you to contact your service provider. Its guidance asks requesters to explain the cause, corrective action and timing, and steps taken to prevent a recurrence. It also says a request does not guarantee removal and the issue should be addressed first.
The process can depend on the list and who controls the IP. For an SBL-listed IP, Spamhaus's SBL FAQ says the end user should contact their system administrator, ISP, or email provider, and that removal requests are made by the ISP responsible for the IP. The PBL guidance explains that PBL entries identify IP space not expected to send directly to destination mail servers; those entries are not necessarily “bad.” Use its checker and request review only when the listing does not fit the IP's legitimate sending role.
Cisco Talos
If the receiver specifically names Cisco Talos sender IP reputation, inspect the IP in the Talos Intelligence Center. Talos provides a Sender IP Reputation Support form for reporting IPs sending malicious email or requesting a reputation correction. The form requires a Cisco account. Talos also provides a separate sender domain support form when the receiver identifies a domain reputation issue.
Treat this as a request for Talos to review its own reputation data, not as a universal DNS blocklist removal process. Use the exact asset named by the receiver and follow the form's current instructions.
After you submit a request
Keep the operator's response with your case notes and check the same provider, list, and sending identifier again. A submitted request is not confirmation of removal. The listing operator controls its data and any removal decision; removal is not guaranteed.
Even when an operator no longer reports a listing, that does not guarantee improved inbox placement. A receiving provider may apply other reputation, authentication, policy, or message-level checks.
For a broader explanation of blocklists, read the email blacklist guide. For the remediation sequence after you identify a hit, continue to the blocklist removal guide.
Read provider blocklist results →