What it is
InterServer's RBL is an internal blocklist maintained by the US hosting provider InterServer to protect their customers from spam. It lists IPs that send spam to InterServer-hosted domains based on complaints and spam trap hits within their network.
How it affects SMTP delivery
This list primarily affects deliverability to domains hosted on InterServer's shared and dedicated hosting infrastructure. It does not impact deliverability to other providers.
What causes a listing
Listings occur from spam complaints or spam trap hits on InterServer-hosted addresses.
How to get removed
Contact InterServer support to submit a removal request. Provide your IP address and evidence that the spam issue has been resolved.
For the full reference catalog, see the email blocklist directory.
Delisting process in detail
The InterServer blocklist (rbl.interserver.net) is operated by InterServer, a US hosting provider. Delisting is handled through interserver.net’s abuse form and typically requires demonstrating that the sending IP is not being used for spam. InterServer responds to delisting requests within 24-48 hours. Because InterServer is a hosting provider first and a blocklist operator second, delisting policies focus on hosting-related abuse patterns.
Prevention practices
InterServer’s blocklist targets IPs that have sent spam to InterServer-hosted mailboxes. Prevention follows standard anti-abuse fundamentals: authenticated sending, list hygiene, complaint monitoring. Because InterServer hosts significant customer volume, their honeypot exposure is meaningful for senders reaching InterServer-hosted addresses. Purchased lists that hit InterServer traps produce prompt listings. Confirmed opt-in and disciplined list hygiene remain the primary prevention practices.
Common listing causes
InterServer listings correlate with observed spam sending to InterServer-hosted mailboxes. Common causes include purchased lists containing InterServer customer addresses, compromised shared-hosting accounts on other providers blasting spam through infrastructure that reaches InterServer, and coordinated spam campaigns targeting InterServer’s customer base. Legitimate senders reaching InterServer-hosted mailboxes typically avoid listings through standard practices.
Related blocklists
Hosting-provider blocklists like InterServer’s operate alongside major public blocklists to catch spam patterns targeting specific customer bases. Similar blocklists include those operated by ISPs and hosting providers for internal filtering. Enterprise senders reaching diverse audiences should monitor major public blocklists (Spamhaus, Barracuda, SpamCop) for broad coverage; provider-specific blocklists like InterServer’s matter when reaching their specific customer base.
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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