RDPSchool is not a separate company or service. The brand has been retired and rdpschool.com now points here permanently.
Same team, same servers, same support — new name. Existing RDPSchool accounts, services and renewals continue exactly as before; only the name and the web address have changed.
Enter an AS number, an IP address or part of a network name to get the autonomous system behind it and the full list of IPv4 and IPv6 prefixes it announces.
AUTONOMOUS SYSTEMS
ASN RESULT
Prefixes are what the network announced in global BGP when the database was last built, so a very recent change may be missing. Network data: iptoasn.com. IP Geolocation by DB-IP, licensed under CC BY 4.0. Database updated 2026-10-17.
HOW TO USE IT
One box accepts all three kinds of input and works out which one you meant.
An AS number (AS24940 or just 24940), any public IP address, or a few letters of the network's name.
A name search lists every matching AS, biggest first. Select one to open its details.
The result shows the network name, registry country, how many IPv4 and IPv6 prefixes it announces and the total IPv4 space.
Copy the IPv4 or IPv6 list as one CIDR per line and feed it to ipset, nftables sets, UFW, a cloud security group or a CDN firewall rule.
The internet is made of tens of thousands of independently run networks: ISPs, mobile operators, clouds, hosting companies, universities and large enterprises. Each one has an autonomous system number and uses BGP to tell its neighbours which IP blocks it can deliver traffic to.
Knowing the ASN behind an address tells you who really carries that traffic, which is often more useful than the city a geolocation database guesses.
When abuse arrives from many addresses on one provider, an ASN's prefix list lets you act once instead of chasing single IPs. Load the list into an ipset or an nftables set and match the set in one rule, which stays fast even with thousands of entries.
The same list works the other way round: allow only your office ISP or your monitoring provider to reach SSH, RDP or an admin panel.
The country shown is where the AS is registered, not where each prefix is used. Global networks such as Cloudflare, Google or Amazon are registered in one country but announce space used on every continent. Use IP Lookup to locate a specific address.
The page lists up to 500 IPv4 and 500 IPv6 prefixes per network, which covers almost every hosting provider and ISP. For the very largest clouds the counts at the top show the full size, and the list notes when it was shortened.
Blocking a large ISP or cloud can cut off real customers, payment callbacks, monitoring and your own access. Add the rule with a log-only or short-lived action first, keep your management address on an allow-list above it, and refresh the prefix list regularly because networks change what they announce.
FREQUENTLY ASKED QUESTIONS