sieveLau

If we accept to use aes-gcm to encrypt the content, the password hashing part would be the next part to be strengthened. After all, md5 is too fast for password...

用v4版本写response matcher，rcode不是0的就forward到另一个上游，直到rcode为0为止就可以了。示例： ``` plugins: - tag: upstream_success type: response_matcher args: rcode: [0] - tag: main_sequence type: sequence args: exec: # 优先返回ipv4结果 - _prefer_ipv4 - ecs_auto - to_google - if: (!...

建议1的难处是上游AdguardTeam的dnsproxy的0.58.0改动，导致只能指定一个IP，我fork的也因此只能锁定dnsproxy为0.57.3。（参考我的这个[备注](https://github.com/sieveLau/mosdns/blob/v4-maintenance/plugin/executable/forward/README.md))