Ubuntu 服务器中的错误：服务器返回错误 NXDOMAIN

Question

我正在运行一个 Ubuntu 服务器 (18.04.1)，几天后我在系统日志中看到这些消息：

systemd-resolved[1059]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.

在收到这些消息时，我无法从外部世界访问我的服务器，只能从我的内部局域网访问。需要几分钟时间，然后可以从其域名再次访问服务器。

系统日志的输出：

11/5/18
1:51:02.000 PM  
Nov  5 13:51:02 server systemd-resolved[1059]: message repeated 12 times: [ Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.]
host =  server source = /var/log/syslog sourcetype =    syslog
11/5/18
1:50:59.000 PM  
Nov  5 13:50:59 server systemd-resolved[1059]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.
host =  server source = /var/log/syslog sourcetype =    syslog
11/5/18
1:50:39.000 PM  
Nov  5 13:50:39 server snapd[1255]: stateengine.go:102: state ensure error: Get https://api.snapcraft.io/api/v1/snaps/sections: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)
host =  server source = /var/log/syslog sourcetype =    syslog
11/5/18
1:44:20.000 PM  
Nov  5 13:44:20 server systemd-resolved[1059]: message repeated 5 times: [ Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.]
host =  server source = /var/log/syslog sourcetype =    syslog
11/5/18
1:44:20.000 PM  
Nov  5 13:44:20 server systemd-resolved[1059]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.
host =  server source = /var/log/syslog sourcetype =    syslog
11/5/18
1:15:24.000 PM  
Nov  5 13:15:24 server systemd-resolved[1059]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.
host =  server source = /var/log/syslog sourcetype =    syslog
11/5/18
1:15:24.000 PM  
Nov  5 13:15:24 server systemd-resolved[1059]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.
host =  server source = /var/log/syslog sourcetype =    syslog
11/5/18
1:07:27.000 PM  
Nov  5 13:07:27 server systemd-resolved[1059]: message repeated 5 times: [ Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.]
host =  server source = /var/log/syslog sourcetype =    syslog
11/5/18
1:07:27.000 PM  
Nov  5 13:07:27 server systemd-resolved[1059]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.
host =  server source = /var/log/syslog sourcetype =    syslog
11/5/18
12:49:57.000 PM 
Nov  5 12:49:57 server systemd-resolved[1059]: message repeated 12 times: [ Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.]

我无法通过谷歌搜索此错误消息找到正确的答案。

谁能帮我？

Answer 1

这就是 systemd 的工作原理：如果systemd-resolve尝试解析未解析的域，它就会记录该消息，该消息可以被忽略。可能还有其他错误情况会发出此警告。

当使用不存在的互联网或内联网域名时，将会出现 NXDOMAIN 错误。它的名字的意思是“不存在的域”。如果无法使用 DNS 解析域名，则会出现称为 NXDOMAIN 的情况。例如， nslookup使用不存在的名称调用可能会返回 的错误 Host whatever.com not found: 3(NXDOMAIN)。

可能导致此问题的一种情况是，当主权威名称服务器上的 DNS 记录更新时，可能需要一些时间才能传播到全局递归 DNS 服务器，而这种情况的发生取决于 DNS 记录的生存时间 (TTL)。

另一种情况可能是您尝试访问的服务器已离线。

就您而言，我认为 NXDOMAIN 错误是症状，但不是您失去与域的连接的原因。事实上，这种情况会及时自行解决，这一事实进一步证实了这与您的 DNS 设置有关的理论。也许清除计算机和浏览器上的 DNS 缓存可能会有所帮助。

输入不存在的域名时，您可能会在http://cachecheck.opendns.com上看到此错误 。该工具可能有助于分析问题。