sing-box/docs/faq/fakeip.md

FakeIP

FakeIP refers to a type of behavior in a program that simultaneously hijacks both DNS and connection requests. It responds to DNS requests with virtual results and restores mapping when accepting connections.

Advantage

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Limitation

• Its mechanism breaks applications that depend on returning correct remote addresses.
• Only A and AAAA (IP) requests are supported, which may break applications that rely on other requests.

Recommendation

• Enable dns.independent_cache unless you always resolve FakeIP domains remotely.
• If using tun, make sure FakeIP ranges is included in the tun's routes.
• Enable experimental.clash_api.store_fakeip to persist FakeIP records, or use dns.rules.rewrite_ttl to avoid losing records after program restart in DNS cached environments.