Research Article
Knocking on IPs: Identifying HTTPS Websites for Zero-Rated Traffic
Table 1
Summary of website identification methods for zero-rating.
| Method | HTTPS | Support | In-band | ESNI and DoH | Free-riding I | Free-riding II | Open set | Known usages |
| Non-HTTPS | | | ✓ | | | ✓ | ✓ | Various ISPs [8, 9] | SNI | ✓ | Post-2006 clients | ✓ | | | ≈ | ✓ | Various ISPs, censorship [40] | Whitelisting IPs | ✓ | CP | ✓ | ✓ | ✓ | ✓ | | Wikipedia zero [3], censorship [40] | DNS | ✓ | | ✓ | | | ✓ | ✓ | Facebook zero [37], censorship [40] | Verify SNI by DNS | ✓ | | | | | ✓ | ✓ | Cisco patent [39] | Network cookies | ✓ | CP | ✓ | ✓ | ? | ? | ? | ? | WPF | ✓ | | ✓ | ✓ | | ≈ | | Censorship [41] | Self-signed | ✓ | Client | ✓ | ✓ | | ✓ | ✓ | Enterprise and surveillance governments [42, 43] | Reverse DNS | ✓ | CP | | ✓ | ≈ | ✓ | ≈ | Antispoofing, OSINT tools (e.g., Maltego) | Open-Knock | ✓ | | | ✓ | ✓ | ≈ | ✓ | |
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“≈” indicates a dependency on the specific zero-rating implementation used.
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