ASN, ISP and Reverse DNS: What Each Field Means
A short reference explaining the network ownership fields you see in any IP lookup: ASN, ISP, organization, and reverse DNS.
When you look up an IP, you usually see fields about who owns and operates the network. These are administrative records, not personal data.
ASN (Autonomous System Number)
An ASN identifies a group of IP networks under a single routing policy — usually an ISP, cloud provider, university, or large company.
ISP
The Internet Service Provider that allocates the address to the end network. For mobile traffic this is the carrier, for home internet it is the broadband provider.
Reverse DNS (PTR)
A hostname associated with the IP. ISPs often use generic templates such as host-203-0-113-10.example-isp.net.
常见问题
Is ASN the same as ISP?
They are closely related but not identical. One ISP can own multiple ASNs, and ASN names are sometimes more technical than the public brand.
相关内容
- What Is My IP Address? A Plain-English GuideA clear, non-technical explanation of what an IP address is, why websites can see it, and what it does — and does not — reveal about you.
- VPN, Proxy, Mobile and Hosting IPs ExplainedModern IP intelligence classifies addresses into residential, mobile, hosting, proxy and VPN buckets. Here is what each means.
来源：ip-api 文档、区域互联网注册机构（ARIN、RIPE、APNIC、LACNIC、AFRINIC）以及 BGP 路由数据。