calivent.orgThis blocklist is no longer operational. DNS queries return NXDOMAIN. Remove calivent.org from MTA configurations to avoid query timeouts.
What it is
CALIVENT was a blocklist project targeting IPs sending malware via email. The project has been discontinued.
How it affects SMTP delivery
No impact. Remove calivent.org from any DNSBL list your MTA still queries.
What causes a listing
N/A, defunct.
How to get removed
No removal necessary.
For the full reference catalog, see the email blocklist directory.
How to confirm the zone is dead
Test it before changing anything. A live DNSBL answers a reversed query with 127.0.0.x when the address is listed, and NXDOMAIN when it is not. A withdrawn zone answers nothing at all, for any query, including its own hostname. Checked in September 2026, calivent.org publishes no address record and returns no DNSBL answer, which is the signature of a zone that has been taken down rather than of a clean IP.
Why a dead zone still costs you
An MTA that still queries a withdrawn zone waits out the DNS timeout on inbound connections. Postfix, Exim and SpamAssassin all treat a DNSBL that fails to answer as a soft failure, so no mail is rejected and nothing is logged as an error; connection setup simply gets slower, and the cost scales with inbound volume. The fix is to delete the zone from the configuration, not to shorten the timeout.
If a bounce sent you here
A dead zone cannot be the source of a current rejection. When a receiver refuses your mail over a blocklist, the SMTP reply names the zone it queried. Read that name from the bounce and look it up in the directory linked above rather than assuming CALIVENT is involved.
About the Author
Alaa · LinkedIn
Email infrastructure specialist with 8+ years of hands-on experience in SMTP, deliverability, and email verification. I’ve configured and troubleshot mail systems across Postfix, Exchange, and cloud relays, managed IP reputation and warmup campaigns, and built verification pipelines processing millions of addresses. My work spans DNS authentication (SPF, DKIM, DMARC, BIMI), bounce handling, blocklist monitoring, and compliance frameworks including CAN-SPAM and GDPR. I write every article on SMTPedia to give email professionals, developers, and marketers the accurate, RFC-grounded reference they need.
About SMTPedia
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