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配置了speed check mode后，不返回cname记录，无法与simple dns plus协同工作。 #1879

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ncluj opened this issue Dec 19, 2024 · 8 comments
Open

配置了speed check mode后，不返回cname记录，无法与simple dns plus协同工作。 #1879

ncluj opened this issue Dec 19, 2024 · 8 comments

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@ncluj
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ncluj commented Dec 19, 2024

问题现象
结构简述：client->simple dns plus -> smartdns
需求背景：之前一直是用simple dns plus，主要图它的实时监控gui和cache。最近因为上游流量有审计，有内网终端可能请求了一些c2c域名被检测到，惹麻烦，想往上游走DoT，可sdp不支持，再试用了smartdns的速度优选功能，觉得很有效果，打算在sdp上游改为smartdns,smartdns开启speed check,上游走DoT。

运行环境
Win10 Ent
simple dns plus 9
smartdns 0.9
4. 涉及的配置(注意去除个人相关信息)
speed-check-mode ping,tcp:80,tcp:443
smartdns 侦听本地网卡 127.0.0.1:53
simple dns plus侦听本地IP 192.168.31.171:53，配置上游dns 127.0.0.1
重现步骤

  1. 不启用speedcheck
    1.1直接请求smartdns
> server 127.0.0.1
默认服务器:  localhost
Address:  127.0.0.1

> www.baidu.com
服务器:  localhost
Address:  127.0.0.1

非权威应答:
非权威应答:
名称:    www.a.shifen.com
Addresses:  240e:ff:e020:9ae:0:ff:b014:8e8b
          240e:ff:e020:966:0:ff:b042:f296
          183.2.172.42
Aliases:  www.baidu.com

1.2 请求simplednsplus

> server 192.168.31.171
默认服务器:  smartdns
Address:  192.168.31.171

> www.baidu.com
服务器:  smartdns
Address:  192.168.31.171

名称:    www.a.shifen.com
Addresses:  240e:ff:e020:966:0:ff:b042:f296
          240e:ff:e020:9ae:0:ff:b014:8e8b
Aliases:  www.baidu.com

正常返回。查看simplednsplus日志，正常通过smartdns返回

10:00:50   Request from 192.168.31.171 for A-record for www.baidu.com.lan
10:00:50   Sending request to 127.0.0.1 (forward server) for A-record for www.baidu.com.lan
10:00:50   Reply from 127.0.0.1 about A-record for www.baidu.com.lan:
10:00:50   -> Answer: SOA-record for <root> = a.root-servers.net [2024121802]
10:00:50   Sending reply to 192.168.31.171 about A-record for www.baidu.com.lan:
10:00:50   -> Header: Server Failure
10:00:50   Request from 192.168.31.171 for AAAA-record for www.baidu.com.lan
10:00:50   Sending request to 127.0.0.1 (forward server) for AAAA-record for www.baidu.com.lan
10:00:51   Reply from 127.0.0.1 about AAAA-record for www.baidu.com.lan:
10:00:51   -> Answer: SOA-record for <root> = a.root-servers.net [2024121802]
10:00:51   Sending reply to 192.168.31.171 about AAAA-record for www.baidu.com.lan:
10:00:51   -> Header: Server Failure
10:00:51   Request from 192.168.31.171 for A-record for www.baidu.com
10:00:51   Sending request to 127.0.0.1 (forward server) for A-record for www.baidu.com
10:00:51   Reply from 127.0.0.1 about A-record for www.baidu.com:
10:00:51   -> Answer: A-record for www.a.shifen.com = 183.2.172.42
10:00:51   Sending reply to 192.168.31.171 about A-record for www.baidu.com:
10:00:51   -> Header: Server Failure
10:00:51   Request from 192.168.31.171 for AAAA-record for www.baidu.com
10:00:51   Sending request to 127.0.0.1 (forward server) for AAAA-record for www.baidu.com
10:00:51   Reply from 127.0.0.1 about AAAA-record for www.baidu.com:
10:00:51   -> Answer: CNAME-record for www.baidu.com = www.a.shifen.com
10:00:51   -> Answer: AAAA-record for www.a.shifen.com = 240e:ff:e020:966:0:ff:b042:f296
10:00:51   -> Answer: AAAA-record for www.a.shifen.com = 240e:ff:e020:9ae:0:ff:b014:8e8b
10:00:51   Sending reply to 192.168.31.171 about AAAA-record for www.baidu.com:
10:00:51   -> Answer: CNAME-record for www.baidu.com = www.a.shifen.com
10:00:51   -> Answer: AAAA-record for www.a.shifen.com = 240e:ff:e020:966:0:ff:b042:f296
10:00:51   -> Answer: AAAA-record for www.a.shifen.com = 240e:ff:e020:9ae:0:ff:b014:8e8b

2.启用speed check mode
2.1 直接请求smartdns

> www.baidu.com
服务器:  localhost
Address:  127.0.0.1

非权威应答:
非权威应答:
名称:    www.a.shifen.com
Addresses:  240e:ff:e020:966:0:ff:b042:f296
          183.2.172.185

返回一条测速后的记录，注意，没有CName记录
2.2请求 simple dns plus

> server  192.168.31.171
默认服务器:  smartdns
Address:  192.168.31.171

> www.baidu.com
服务器:  smartdns
Address:  192.168.31.171

*** smartdns 找不到 www.baidu.com: Server failed

失败了。
调取simplednsplus日志


10:09:06   Request from 192.168.31.171 for A-record for www.baidu.com.lan
10:09:06   Sending request to 127.0.0.1 (forward server) for A-record for www.baidu.com.lan
10:09:07   Reply from 127.0.0.1 about A-record for www.baidu.com.lan:
10:09:07   -> Answer: SOA-record for <root> = a.root-servers.net [2024121802]
10:09:07   Sending reply to 192.168.31.171 about A-record for www.baidu.com.lan:
10:09:07   -> Header: Server Failure
10:09:07   Request from 192.168.31.171 for AAAA-record for www.baidu.com.lan
10:09:07   Sending request to 127.0.0.1 (forward server) for AAAA-record for www.baidu.com.lan
10:09:07   Reply from 127.0.0.1 about AAAA-record for www.baidu.com.lan:
10:09:07   -> Answer: SOA-record for <root> = a.root-servers.net [2024121802]
10:09:07   Sending reply to 192.168.31.171 about AAAA-record for www.baidu.com.lan:
10:09:07   -> Header: Server Failure
10:09:07   Request from 192.168.31.171 for A-record for www.baidu.com
10:09:07   Sending request to 127.0.0.1 (forward server) for A-record for www.baidu.com
10:09:07   Reply from 127.0.0.1 about A-record for www.baidu.com:
10:09:07   -> Answer: A-record for www.a.shifen.com = 183.2.172.42
10:09:07   Sending reply to 192.168.31.171 about A-record for www.baidu.com:
10:09:07   -> Header: Server Failure
10:09:07   Request from 192.168.31.171 for AAAA-record for www.baidu.com
10:09:07   Sending request to 127.0.0.1 (forward server) for AAAA-record for www.baidu.com
10:09:07   Reply from 127.0.0.1 about AAAA-record for www.baidu.com:
10:09:07   -> Answer: AAAA-record for www.a.shifen.com = 240e:ff:e020:966:0:ff:b042:f296
10:09:07   Sending reply to 192.168.31.171 about AAAA-record for www.baidu.com:
10:09:07   -> Header: Server Failure

如直接请求的一致，向127.0.0.1转发了请求，直接返回了 www.a.shifen.com 的A记录和AAAA记录，但是simplednsplus不认可，可能觉得跟www.baidu.com没关系，忽略不计了，返回了个Server Failure。

这是simplednsplus的问题，还是smartdns的问题。如果是simplednsplus的问题，smartdns有没有个选项，可以在优选测速后的ip后，还把cname记录给返回。

交叉测试：使用www.google.com域名测试，返回的是www.google.com的A记录，没问题。使用其他带cdn的域名测试，都是这个情况。

smartdns的日志供参考：


2024-12-19 10:06:56.652:INFO: Smart-DNS 🐋 0.9.0 🕙 Sun Oct 13 10:00:51 UTC 2024 starting
2024-12-19 10:06:56.654:INFO: loading configuration from: "./smartdns.conf"
2024-12-19 10:06:56.660:INFO: whoami 👉 smartdns
2024-12-19 10:06:56.671:INFO: num workers: 8
2024-12-19 10:06:56.674:INFO: upstream server: https://cloudflare-dns.com/dns-query [Group: []]
2024-12-19 10:06:56.677:INFO: upstream server: https://dns.alidns.com/dns-query [Group: default]
2024-12-19 10:06:56.677:INFO: upstream server: https://doh.pub/dns-query [Group: default]
2024-12-19 10:06:56.678:INFO: cache: size(32768)
2024-12-19 10:06:56.678:INFO: cache persist: NO
2024-12-19 10:06:56.679:INFO: domain prefetch: OFF
2024-12-19 10:06:56.679:INFO: speed check mode: ICMP, TCP:80, TCP:443
2024-12-19 10:06:56.686:WARN:smartdns::dns_client:118: bootstrap-dns must use ip addess, Domain("cloudflare-dns.com")
2024-12-19 10:06:56.686:WARN:smartdns::dns_client:137: not bootstrap-dns found, use system_conf instead.
2024-12-19 10:06:56.689:DEBUG:smartdns::server::net:65: binding UDP to 127.0.0.1:53
2024-12-19 10:06:56.697:INFO: listening for UDP on 127.0.0.1:53
2024-12-19 10:06:56.698:DEBUG:smartdns::server::net:65: binding UDP to [::]:53
2024-12-19 10:06:56.698:INFO: listening for UDP on [::]:53
2024-12-19 10:06:56.698:INFO:
2024-12-19 10:06:56.699:INFO:      _____                      _       _____  _   _  _____
2024-12-19 10:06:56.699:INFO:     / ____|                    | |     |  __ \| \ | |/ ____|
2024-12-19 10:06:56.699:INFO:    | (___  _ __ ___   __ _ _ __| |_    | |  | |  \| | (___
2024-12-19 10:06:56.700:INFO:     \___ \| '_ ` _ \ / _` | '__| __|   | |  | | . ` |\___ \
2024-12-19 10:06:56.700:INFO:     ____) | | | | | | (_| | |  | |_    | |__| | |\  |____) |
2024-12-19 10:06:56.700:INFO:    |_____/|_| |_| |_|\__,_|_|   \__|   |_____/|_| \_|_____/
2024-12-19 10:06:56.701:INFO:
2024-12-19 10:06:56.701:INFO: awaiting connections...
2024-12-19 10:06:56.701:INFO: server starting up
2024-12-19 10:07:01.404:DEBUG:smartdns::server::udp:45: received udp request from: 127.0.0.1:55506
2024-12-19 10:07:01.405:DEBUG:smartdns::app:366: request:237 src:udp://127.0.0.1#55506 type:QUERY dnssec:false QUERY:www.baidu.com.lan.:A:IN qflags:RD
2024-12-19 10:07:01.406:DEBUG:smartdns::dns_mw_ns:97: query name: www.baidu.com.lan. type: A via [Group: default]
2024-12-19 10:07:01.410:DEBUG:smartdns::dns_client::bootstrap:1330: lookup nameserver doh.pub A, [1.12.12.12, 120.53.53.53]
2024-12-19 10:07:01.414:DEBUG:smartdns::dns_client::bootstrap:1330: lookup nameserver dns.alidns.com A, [223.6.6.6, 223.5.5.5]
2024-12-19 10:07:01.562:DEBUG:smartdns::server::udp:45: received udp request from: 127.0.0.1:55508
2024-12-19 10:07:01.562:DEBUG:smartdns::app:366: request:238 src:udp://127.0.0.1#55508 type:QUERY dnssec:false QUERY:www.baidu.com.lan.:AAAA:IN qflags:RD
2024-12-19 10:07:01.564:DEBUG:smartdns::dns_mw_ns:97: query name: www.baidu.com.lan. type: AAAA via [Group: default]
2024-12-19 10:07:01.565:DEBUG:smartdns::dns_mw_ns:97: query name: www.baidu.com.lan. type: A via [Group: default]
2024-12-19 10:07:01.628:DEBUG:smartdns::server::udp:45: received udp request from: 127.0.0.1:55509
2024-12-19 10:07:01.629:DEBUG:smartdns::app:366: request:239 src:udp://127.0.0.1#55509 type:QUERY dnssec:false QUERY:www.baidu.com.:A:IN qflags:RD
2024-12-19 10:07:01.630:DEBUG:smartdns::dns_mw_ns:97: query name: www.baidu.com. type: A via [Group: default]
2024-12-19 10:07:01.872:DEBUG:smartdns::dns_mw_ns:466: Speed test www.baidu.com. ICMP ping [183.2.172.42, 183.2.172.185]
2024-12-19 10:07:01.890:DEBUG:smartdns::dns_mw_ns:477: The fastest ip of www.baidu.com. is 183.2.172.185, delay: 17.0652ms
2024-12-19 10:07:01.891:DEBUG:smartdns::server::udp:45: received udp request from: 127.0.0.1:55510
2024-12-19 10:07:01.891:DEBUG:smartdns::app:366: request:240 src:udp://127.0.0.1#55510 type:QUERY dnssec:false QUERY:www.baidu.com.:AAAA:IN qflags:RD
2024-12-19 10:07:01.892:DEBUG:smartdns::dns_mw_ns:97: query name: www.baidu.com. type: AAAA via [Group: default]
2024-12-19 10:07:01.893:DEBUG:smartdns::dns_mw_ns:97: query name: www.baidu.com. type: A via [Group: default]
2024-12-19 10:07:01.913:DEBUG:smartdns::dns_mw_ns:466: Speed test www.baidu.com. ICMP ping [183.2.172.185, 183.2.172.42]
2024-12-19 10:07:01.917:DEBUG:smartdns::dns_mw_ns:466: Speed test www.baidu.com. ICMP ping [183.2.172.42, 183.2.172.185]
2024-12-19 10:07:01.925:DEBUG:smartdns::dns_mw_ns:466: Speed test www.baidu.com. ICMP ping [240e:ff:e020:966:0:ff:b042:f296, 240e:ff:e020:9ae:0:ff:b014:8e8b]
2024-12-19 10:07:01.926:DEBUG:smartdns::dns_mw_ns:466: Speed test www.baidu.com. TCP:80 ping [240e:ff:e020:966:0:ff:b042:f296, 240e:ff:e020:9ae:0:ff:b014:8e8b]
2024-12-19 10:07:01.927:DEBUG:smartdns::dns_mw_ns:466: Speed test www.baidu.com. TCP:443 ping [240e:ff:e020:966:0:ff:b042:f296, 240e:ff:e020:9ae:0:ff:b014:8e8b]
2024-12-19 10:07:01.931:DEBUG:smartdns::dns_mw_ns:477: The fastest ip of www.baidu.com. is 183.2.172.185, delay: 17.4527ms
2024-12-19 10:09:05.625:DEBUG:smartdns::server::udp:45: received udp request from: 127.0.0.1:56472
2024-12-19 10:09:05.627:DEBUG:smartdns::app:366: request:241 src:udp://127.0.0.1#56472 type:QUERY dnssec:false QUERY:171.31.168.192.in-addr.arpa.:PTR:IN qflags:RD
2024-12-19 10:09:06.989:DEBUG:smartdns::server::udp:45: received udp request from: 127.0.0.1:65529
2024-12-19 10:09:06.990:DEBUG:smartdns::app:366: request:24674 src:udp://127.0.0.1#65529 type:QUERY dnssec:false QUERY:www.baidu.com.lan.:A:IN qflags:RD
2024-12-19 10:09:06.992:DEBUG:smartdns::dns_mw_ns:97: query name: www.baidu.com.lan. type: A via [Group: default]
2024-12-19 10:09:07.113:DEBUG:smartdns::server::udp:45: received udp request from: 127.0.0.1:61252
2024-12-19 10:09:07.113:DEBUG:smartdns::app:366: request:19840 src:udp://127.0.0.1#61252 type:QUERY dnssec:false QUERY:www.baidu.com.lan.:AAAA:IN qflags:RD
2024-12-19 10:09:07.115:DEBUG:smartdns::dns_mw_ns:97: query name: www.baidu.com.lan. type: AAAA via [Group: default]
2024-12-19 10:09:07.115:DEBUG:smartdns::dns_mw_ns:97: query name: www.baidu.com.lan. type: A via [Group: default]
2024-12-19 10:09:07.203:DEBUG:smartdns::server::udp:45: received udp request from: 127.0.0.1:52251
2024-12-19 10:09:07.203:DEBUG:smartdns::app:366: request:8155 src:udp://127.0.0.1#52251 type:QUERY dnssec:false QUERY:www.baidu.com.:A:IN qflags:RD
2024-12-19 10:09:07.205:DEBUG:smartdns::dns_mw_ns:97: query name: www.baidu.com. type: A via [Group: default]
2024-12-19 10:09:07.223:DEBUG:smartdns::dns_mw_ns:466: Speed test www.baidu.com. ICMP ping [183.2.172.42, 183.2.172.185]
2024-12-19 10:09:07.238:DEBUG:smartdns::dns_mw_ns:466: Speed test www.baidu.com. ICMP ping [183.2.172.185, 183.2.172.42]
2024-12-19 10:09:07.243:DEBUG:smartdns::dns_mw_ns:477: The fastest ip of www.baidu.com. is 183.2.172.42, delay: 18.3772ms
2024-12-19 10:09:07.244:DEBUG:smartdns::server::udp:45: received udp request from: 127.0.0.1:39780
2024-12-19 10:09:07.244:DEBUG:smartdns::app:366: request:63461 src:udp://127.0.0.1#39780 type:QUERY dnssec:false QUERY:www.baidu.com.:AAAA:IN qflags:RD
2024-12-19 10:09:07.245:DEBUG:smartdns::dns_mw_ns:97: query name: www.baidu.com. type: AAAA via [Group: default]
2024-12-19 10:09:07.246:DEBUG:smartdns::dns_mw_ns:97: query name: www.baidu.com. type: A via [Group: default]
2024-12-19 10:09:07.264:DEBUG:smartdns::dns_mw_ns:466: Speed test www.baidu.com. ICMP ping [240e:ff:e020:9ae:0:ff:b014:8e8b, 240e:ff:e020:966:0:ff:b042:f296]
2024-12-19 10:09:07.265:DEBUG:smartdns::dns_mw_ns:466: Speed test www.baidu.com. TCP:80 ping [240e:ff:e020:9ae:0:ff:b014:8e8b, 240e:ff:e020:966:0:ff:b042:f296]
2024-12-19 10:09:07.268:DEBUG:smartdns::dns_mw_ns:466: Speed test www.baidu.com. TCP:443 ping [240e:ff:e020:9ae:0:ff:b014:8e8b, 240e:ff:e020:966:0:ff:b042:f296]
2024-12-19 10:09:07.270:DEBUG:smartdns::dns_mw_ns:466: Speed test www.baidu.com. ICMP ping [183.2.172.42, 183.2.172.185]

信息收集

  1. 将/var/log/smrtdns.log日志作为附件上传(注意去除个人相关信息)。
  2. 如进程异常，请将coredump功能开启，上传coredump信息文件，同时上传配套的smartdns进程文件。
    在自定义界面，开启设置->自定义设置->生成coredump配置，重现问题后提交coredump文件
    coredump文件在/tmp目录下
@PikuZheng
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尝试配置 force-no-CNAME yes

大致上看这应该是 simplednsplus 转发不规范。一个DNS转发器处理具有cname的双栈域名时应该向上游发起两次请求，第一次查询 www.baidu.com A。上游返回cname=www.a.shifen.com后，应使用 www.a.shifen.com AAAA发起第二次查询。

@ncluj
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ncluj commented Dec 19, 2024

从simplednsplus日志，以及nslookup直接查询smartdns看，simplednsplus发起查询www.baidu.com的A记录，smartdns直接返回www.a.shifen.com的A记录，而不是返回cname（好像和您说的正好相反）。
如果不配置speedcheck，smartdns既返回cname=shifen.com，又返回shifen.com的A记录。是否smartdns的策略就是，测速后只返回速度最好的A记录，不返回cname。能否通过源码验证一下。然后，这样不返回cname是smartdns返回不规范，还是simplednsplus丢弃不规范。我也看不懂规范原文，麻烦您解读下看看。

我个人理解，simplednsplus请求 a.com的A记录，上游返回b.com的A记录(没有cname记录说明a.com=b.com），丢弃这个数据是可以理解的。好像有个说明是，防止dns污染防护吧。

对了。force-no-CNAME yes试过了，没用。

您可以直接在smartdns重现，配置了speedcheck后，请求www.baidu.com，直接返回shifen.com的A记录，没有cname.

@ncluj
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ncluj commented Dec 19, 2024

图片
simplednsplus这段文档，好像说的是这个特性。我英文不好，劳烦您看下。

@PikuZheng
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implednsplus发起查询www.baidu.com的A记录，smartdns直接返回www.a.shifen.com的A记录，而不是返回cname（好像和您说的正好相反）。

根据我的测试，smartdns 在配置了speed-check-mode ping时能够正确返回cname和a
image

在配置了 speed-check-mode none时也同时返回了cname和a
image

@PikuZheng
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image
是这个软件吗？配置上游为smartdns 没问题啊

另外都windows了，为什么不用自带的dns server组件或者unbound（我自己在windows上是用unbound作为dns服务器的

@ncluj
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ncluj commented Dec 19, 2024 •
edited
Loading

观察到您是用linux dig命令测试，我也试了一下。结果却还是不返回cname 。截图如下：
图片
我精简了配置文件，完整的配置文件如下：


server-name smartdns
bind :53
bind [::]:53

speed-check-mode ping
log-level info

server https://cloudflare-dns.com/dns-query  -bootstrap-dns -exclude-default-group
server https://dns.alidns.com/dns-query
server https://doh.pub/dns-query

观察到您是使用的linux下的c版本，我尝试装个再测试一下。我用的是rust版本

Windows | smartdns-rs https://github.com/mokeyish/smartdns-rs | Rust版本SmartDNS

Rust版本没有单独的issue，只能贴到这儿。

@ncluj
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ncluj commented Dec 19, 2024

image 是这个软件吗？配置上游为smartdns 没问题啊

另外都windows了，为什么不用自带的dns server组件或者unbound（我自己在windows上是用unbound作为dns服务器的

谢谢您的回复。一个我看您这返回了多个IP，您这没有启用speed check mode。我的问题只在启用了speed check mode出现。二个，您是否运行的是Rust版本的smartdns.毕竟Win下只能用这个版本。三个，题外话，我用simpledns一个是有个gui比较好观察实时日志和实时负荷，二个比较轻量好配置。
再次感谢您的测试与回复，能不能劳烦您用rust版本，开启speed check mode 再帮我重现一下，是否有这个情况。

@PikuZheng
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PikuZheng commented Dec 19, 2024 •
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rust归隔壁管 https://github.com/mokeyish/smartdns-rs/issues

观察到您是用linux dig命令测试，我也试了一下。

我用的是kdig，不是dig

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