An email blocklist check starts at the list operator, not at an aggregator. A domain blocklist hit follows your domain across every server and IP you send from. An IP blocklist hit does not. So if you changed servers and mail is still rejected, check each domain in the message separately: the visible From domain, the MAIL FROM (envelope) domain, the HELO hostname, and any link or tracking domains in the body.
Domain blocklist vs IP blocklist
The Spamhaus Domain Block List (DBL) lists domains only. It does not support IP addresses: an IP query against the DBL returns 127.0.1.255, which is an error, not a listing (Spamhaus DBL FAQ). IP lists work the other way. ZEN is Spamhaus's combined IP list and contains the SBL, CSS, XBL and PBL (Spamhaus ZEN). A ZEN hit is about an IP address, not a domain, and changing servers will not clear a domain listing.
ArawaMail's documentation does not describe a blocklist checker, a published sending IP, or a delisting workflow. What it does document is the custom MAIL FROM domain set up when you activate sending, together with DKIM CNAME records and MAIL FROM MX and SPF records. A listing on that MAIL FROM domain is a domain problem, not an IP problem.
How to run an email blocklist check
- Open the Spamhaus IP and Domain Reputation Checker at check.spamhaus.org and look up the domain itself, not an IP address.
- Repeat the lookup for every domain the receiving server sees. Spamhaus recommends checking the reverse DNS name of the connecting IP, the HELO/EHLO domain and the MAIL FROM domain against the DBL before the message is accepted, and the domains in headers and body during content checks (Spamhaus SMTP checks).
- Write down the exact list and return code. Current DBL codes are 127.0.1.2 (low-reputation or spam domain), 127.0.1.4 (phishing), 127.0.1.5 (malware), 127.0.1.6 (botnet C&C) and 127.0.1.102 to 127.0.1.106 for abused legitimate domains (Spamhaus return codes). Codes above 127.0.1.100 are meant for message-content checks, not for rejecting a sender outright.
- Only then check the sending IP against ZEN for context, and keep that result separate from the domain diagnosis.
Aggregators such as MX Toolbox show whether a name appears on public DNS blocklists. They are useful for a quick look, but they are not inbox-placement tests. Use the operator's own lookup when the result will drive a removal request.
Newly seen domains and CSS listings
A brand-new domain can show up on the Spamhaus Zero Reputation Domain list (ZRD). ZRD lists domains Spamhaus has first observed in the last 24 hours, with return codes 127.0.2.2 to 127.0.2.24 showing how many hours ago, and removes them automatically after 24 hours (Spamhaus ZRD FAQ). That is not a spam verdict and needs no delisting request.
CSS is an IP list. Spamhaus says CSS listings normally expire three days after the last spam detection, that the cause must be fixed before you request removal through the checker, and that an IP is re-listed quickly if the problem continues. It also advises checking the related domains, because domain and IP reputation are linked (Spamhaus CSS FAQ).
What a clean check does not mean
A clean blocklist check does not guarantee inbox placement. Mailbox providers weigh many signals, including authentication, complaints and engagement. Treat a clean result as one input, and test placement separately before a large send.
Related reading
- Why your emails go to spam, for general placement signals
- Domain reputation vs IP reputation
- Amazon SES suppression lists, because a provider suppression list is not a public blocklist
- How to test inbox placement before a major send
- How ArawaMail sets up DNS
FAQ
Is a domain blocklist the same as an IP blocklist?
No. A domain listing follows the domain to every IP you send from. An IP listing stays with that IP.
Which identifier should I check?
The From domain, the MAIL FROM domain, the HELO hostname, the reverse DNS name of the sending IP, and any link or tracking domains in the body.
Can I look up an IP address on the DBL?
No. The DBL returns the error code 127.0.1.255 for IP queries. Use ZEN for IP addresses.
Does a clean check mean my mail will reach the inbox?
No. Blocklist status is one signal among many.
Does ArawaMail show blocklist status?
ArawaMail's documentation does not include a blocklist checker or a delisting workflow, so use the list operator's lookup.
Want to check your authentication records while you are at it? Try the free ArawaMail email tools.