outbound/naive attempts IPv6 UDP connection to [2001:4860:4860::8888]:443 despite strategy: ipv4_only

### Operating system iOS ### System version 26.4.2 ### Installation type sing-box for iOS Graphical Client ### If you are using a graphical client, please provide the version of the client. 1.14.0-alpha.18 ### Version ```shell ``` ### Description The `naive` outbound spontaneously attempts a UDP connection to `[2001:4860:4860::8888]:443` (Google IPv6 DNS address), even though: - Global `dns.strategy` is set to `ipv4_only` - All `AAAA` queries are rejected via DNS rules - `domain_resolver` is explicitly set on the naive outbound - No IPv6 route exists on the device This is not traffic routed into the naive outbound from inbound — it appears to be internal behavior of the naive outbound itself, triggered during or after establishing an outbound TCP connection. Switching the default outbound from `naive` to `anytls` eliminates the error entirely, confirming this is specific to the naive outbound implementation. ## Relevant Configuration { "dns": { "strategy": "ipv4_only", "servers": [ { "tag": "hosts_fix", "type": "hosts", "predefined": { "dns.alidns.com": ["223.5.5.5", "223.6.6.6"], "cloudflare-dns.com": ["1.1.1.1", "1.0.0.1"] } }, { "type": "https", "tag": "alidns", "server": "dns.alidns.com", "domain_resolver": "hosts_fix", "detour": "DIRECT", "path": "/dns-query" }, { "type": "fakeip", "tag": "fakeip", "inet4_range": "198.18.0.0/15" } ], "rules": [ { "query_type": ["AAAA", "SVCB", "HTTPS", "PTR"], "action": "reject" } ] }, "outbounds": [ { "type": "naive", "tag": "Naive", "server": "example.com", "server_port": 443, "username": "user", "password": "pass", "domain_resolver": "alidns", "udp_over_tcp": { "enabled": true, "version": 2 }, "quic": false, "tls": { "enabled": true, "server_name": "example.com" } } ] } ### Reproduction 1. Set dns.strategy to ipv4_only 2. Add a DNS rule to reject all AAAA queries 3. Configure a naive outbound with domain_resolver pointing to a direct DNS server 4. Enable udp_over_tcp on the naive outbound 5. Use the naive outbound as the default proxy 6. Browse normally for a few minutes Result: ERROR outbound/naive[Naive]: open UDP connection to [2001:4860:4860::8888]:443: connect: no route to host appears repeatedly in logs. ### Logs ```shell DEBUG outbound/naive[Naive]: open UDP connection to [2001:4860:4860::8888]:443 ERROR outbound/naive[Naive]: open UDP connection to [2001:4860:4860::8888]:443: dial en0 (24): dial udp [2001:4860:4860::8888]:443: connect: no route to host DEBUG outbound/naive[Naive]: open TCP connection to 123.456.78.9:443 ``` ### Supporter - [x] I am a [sponsor](https://github.com/sponsors/nekohasekai/) ### Integrity requirements - [x] I confirm that I have read the documentation, understand the meaning of all the configuration items I wrote, and did not pile up seemingly useful options or default values. - [x] I confirm that I have provided the server and client configuration files and process that can be reproduced locally, instead of a complicated client configuration file that has been stripped of sensitive data. - [x] I confirm that I have provided the simplest configuration that can be used to reproduce the error I reported, instead of depending on remote servers, TUN, graphical interface clients, or other closed-source software. - [x] I confirm that I have provided the complete configuration files and logs, rather than just providing parts I think are useful out of confidence in my own intelligence.