- Operator
- System 5 Hosting
- Zone
- all.s5h.net
- Lists
- IP addresses
- Status
- Active
- Severity
- Standard
- Removal
- automatic self-delist by visiting the page from the listed IP: www.usenix.org.uk/content/rbl.html
- Cost
- free
- Turnaround
- near-instant automatic; manual 30+ min
- Auto-expiry
- 5s DNS TTL
What is s5h.net?
s5h.net is a single-operator list: it records IP addresses that sent spam or attack traffic to the operator's servers. Its footprint is small and it sits in the long tail of blocklists some servers add to scoring, so a listing rarely blocks mail on its own but does point at something worth checking.
The DNS TTL on the zone is five seconds, so a delisting is visible to receivers almost immediately.
How serious is a s5h.net listing?
Standard: a smaller footprint, used mainly as a scoring signal by some receivers. Fix the cause it points at; weigh the listing itself calmly. The lookup at www.usenix.org.uk/content/rbl.html is the reference for whether you are listed today.
Why your IP got listed
What the operator lists: Spam or attack traffic at the operator's own servers.
Why there is no removal form, and how the listing clears
automatic self-delist by visiting the page from the listed IP. There is no form and nobody to write to; the list rebuilds from its own observations, and an entry ages out on its own (5s DNS TTL) once the behavior it recorded stops.
- 1
Fix the cause; there is no form to fill
Spam or attack traffic at the operator's own servers. Automatic self-delist by visiting the page from the listed IP.
- 2
Wait for the listing to age out
Auto-expiry: 5s DNS TTL. Typical turnaround: near-instant automatic; manual 30+ min. Nothing you send to the operator shortens it.
- 3
Verify with the operator's lookup
www.usenix.org.uk/content/rbl.html shows the current state; receivers' caches can lag it by hours.
- 01Listing confirmedwww.usenix.org.uk/content/rbl.html
- 02Fix the causeno form to fill
- 03Wait5s DNS TTL
- 04Verifynear-instant automatic
cost: free
How long removal takes
Typical turnaround: near-instant automatic; manual 30+ min. Automatic expiry: 5s DNS TTL. Cost: free.
Frequently asked questions
How do I get removed from s5h.net?
There is no removal form: automatic self-delist by visiting the page from the listed IP. Fix the cause and the listing clears on its own (5s DNS TTL; typically near-instant automatic; manual 30+ min).
How long does a s5h.net listing last?
Automatic expiry: 5s DNS TTL. Removal turnaround: near-instant automatic; manual 30+ min. A listing that returns after clearing means the cause is still live.
Does s5h.net removal cost anything?
Free. No third party can remove a IP from s5h.net faster than the operator's own process, so paid "express delisting" offers add nothing.
What does s5h.net list?
IP addresses: Spam or attack traffic at the operator's own servers. Zones: all.s5h.net.
How do I check whether I am on s5h.net?
Use the operator's lookup at www.usenix.org.uk/content/rbl.html, or the live check on this page, which queries all.s5h.net directly.
Record checked against the operator's site on ; the whole set was last reviewed on . Cells that say undocumented or not found are gaps in the operator's own material, left as they are.