s5h.net is a community-run blocklist of IP addresses seen sending spam. It has modest adoption and provides self-service removal.
Why an IP gets listed on s5h.net
Blocklists add an IP when they see evidence of spam or abuse from it: mail hitting spam traps, a compromised server sending on behalf of a botnet, an open relay or proxy, or a sudden spike in unsolicited mail. Shared hosting and cloud IPs can also inherit a bad reputation from a previous tenant. It has moderate adoption; a listing may affect some receivers but rarely causes a broad delivery failure on its own.
How to delist from s5h.net
To delist from s5h.net: first fix the underlying cause (secure the host, stop the offending mail, close any open relay or proxy), then submit a removal request through the official form:
Delisting only sticks if the root cause is fixed first. Run the full Mail Health Report to catch the SPF, DKIM, DMARC or reverse-DNS problems that often cause listings.
Frequently asked questions
How do I check if my IP is on s5h.net?
Enter your mail server's IP address (or your domain) in the checker above. It queries s5h.net live and tells you immediately whether the IP is listed, along with how many other blocklists list it.
How long does it take to get delisted from s5h.net?
Once you have fixed the underlying issue and submitted the removal request, s5h.net typically processes delisting within a few hours to a few days.
Will a s5h.net listing stop my email being delivered?
It has moderate adoption; a listing may affect some receivers but rarely causes a broad delivery failure on its own.