How To Check The Japanese Native IP By Combining WHOIS And Routing Information. Detailed Steps

When determining whether an IP is a Japanese native IP, the best strategy is to combine data from multiple sources: authoritative WHOIS registration information, BGP/routing perspectives and mainstream GeoIP databases. The best practice is to use authoritative routing and autonomous system (ASN) information as the core, supplemented by WHOIS registration organization and contact information, and then use multiple GeoIP services to cross-verify. The cheapest way is to use free public WHOIS queries and public Looking Glass or Route Views services, and use the free GeoIP query interface to get preliminary conclusions - but be aware that the free data may be delayed or incomplete.

Relying solely on the GeoIP library or a single WHOIS record is prone to errors. WHOIS provides the registration subject, registration time and allocation unit of the IP block, and routing information (such as BGP origin AS, routing path) can reflect the actual bearer and reachable path of IP in the Internet. The combination of the two can determine whether the IP resides "natively" in the Japanese network, or appears to be in Japan through ISP/proxy, CDN or cross-border hosting.

Before taking action, clarify the purpose of the inquiry (operations, compliance or security audit) and ensure compliance with local and target network laws and policies. Only conduct public information queries and permitted connectivity tests to avoid unauthorized intrusions or large-scale scanning.

First confirm the IP or IP segment to be verified. Record the IP's reverse DNS, TLS certificate information, website WHOIS (domain name) and other public clues, which can provide background for subsequent judgments. Avoid using invasive tools at this stage and only do passive information collection.

Use a regional registration authority (such as APNIC) or a general WHOIS service to query the registration record of the IP block, focusing on the registration object (organization), address, registration email and assigned remarks. If the registration subject is a Japanese local ISP or company, and the address and contact information are in Japan, this is one of the important evidences to determine that it is a Japanese native IP.

View the origin AS (Origin AS) and AS path of the IP through the public BGP view or Looking Glass service. If the origin AS is a Japanese ISP/ASN and the routing path converges in the Japanese local network, it means that the probability of the traffic being reachable in Japan is high. On the contrary, if the origin AS is a foreign ASN but is forwarded through Japan, it may be that the overseas network is transited through Japan.

Submit the IP to multiple GeoIP databases (commercial and free) for comparison, and observe the consistency of geographical location, city, longitude and latitude. If most databases point to Japan and are consistent with WHOIS/ASN information, the confidence in judgment can be improved. Note that GeoIP is not absolutely accurate, especially for dynamic IPs, hosting services and CDN nodes.

This is further supported by passive logs (such as access records, server country code) and public services (such as CDN edge node information, certificate organization column). If active connectivity verification is required, authorization should be obtained first and only basic connectivity tests should be performed to avoid scanning or intrusion attempts.

Score based on whether the WHOIS registration subject is a Japanese organization, whether the origin AS belongs to Japan, most of the GeoIP points to Japan, and whether the reverse DNS/certificate information is consistent. The absence or conflict of any element will reduce the credibility of the conclusion. It is recommended to give three confidence levels of high, medium and low and record the evidence chain.

Be wary of misjudgments caused by CDNs, cloud services, multinational ISPs and IP sublease; some registrars or hosting companies register IP registration information in overseas institutions; the GeoIP database update lags behind and has poor support for mobile or dynamic IPs. When conflicting evidence is encountered, the route origin and ASN information will be trusted first.

You can refer to APNIC/RIPE/ARIN's WHOIS query, public BGP views (Route Views, RIPE RIS) and the databases of major GeoIP providers. You can also observe routing details using the ISP or exchange point's Looking Glass page. Use these public sources to help form a complete judgment.

Accurately determine whether a server or client is Japanese native IP, which is helpful for compliance audits, regional deployment and access control policies. Combining WHOIS and routing data can significantly improve the accuracy of judgment, but it must be premised on compliance and minimizing intrusions. All query evidence must be recorded and if necessary, contact the registration operator for further confirmation.