A datacenter proxy in the right country still resolves to a hosting ASN

The far-end server reads the IP's ASN, and IP intelligence providers sort most ASN blocks into roughly hosting, residential or mobile ^[5]. A datacenter proxy or VPN exit in the right country resolves to a hosting ASN because that is genuinely what it is ^[4]. Put a consumer SIM from a real carrier behind the same test and it resolves to mobile for the same reason ^[7].

According to the post, platforms that maintain IP reputation scoring use that class as a signal independent of the country field, and that group by now includes most app stores, ad networks and payment processors ^[6]. So the country assertion passes while the session is routed down a different code path than a real subscriber would get. The team finds out when a support ticket describes a payment flow nobody on it has seen ^[9].

The script is small. It builds a requests Session, sets the proxy from a PROXY_URL environment variable, sets Accept-Language to en-SG, then GETs ipapi.co/json/ and prints ip, org and mobile ^[8]. The post says org should hold a carrier name and not a hosting company, and that mobile is a boolean some providers report separately and worth checking even when org looks right ^[10]. On the third field, the author wrote that country is "the field everyone checks first and the one that matters least here" ^[11]. The read costs one extra GET per session ^[20].

The interest is disclosed in the second paragraph of the post. "I run a mobile proxy network on real SIM cards in Singapore, and this came out of running it," the author wrote ^[12]. The post does not name the platform on which the payment flow diverged, or how often it happens ^[21]. Against your own proxy pool the claim is a one-request experiment. That is the part I find persuasive: point the session at the pool you already pay for and read the org string ^[8].

A clean ASN does not make the rest of the flow correct ^[15]. Following redirects to the store URL shows which region the app store resolved the session into ^[16]. The CDN response headers cf-ipcountry, x-amz-cf-pop, x-geo and x-country show which edge and geo-routing bucket served the bytes ^[17]. That matters when region-specific assets or feature flags come from a CDN and not from the store ^[17]. Beyond country, that is four checks on one session ^[19].

For login, cart and checkout the post says to hold the same session and the same proxy connection through every step. A proxy that rotates IP on each new connection hands you a different IP mid-flow, breaks session cookies and sometimes trips fraud checks a real single-session user would never hit ^[13]. Then there is the scheme string, one character apart ^[18]: socks5h:// routes the hostname lookup through the tunnel, socks5:// resolves it locally ^[14]. Without the h the HTTP request exits the intended IP while the DNS query left from the tester's real location, and the post says some platforms cross-reference the two and flag the mismatch ^[14].