今天分析日志发现一个陌生URL，无法访问，想要查看URL头部信息，于是：
[root@cent7 ~]#curl -I http://www.w3.org/Help/Webmaster
curl: (56) Recv failure: Connection reset by peer
报错意思为对等端重置连接，不懂查了一下
解决方法如下：
[root@cent7 ~]#curl -I https://www.w3.org/Help/Webmaster
HTTP/1.1 200 OK
date: Thu, 27 May 2021 08:07:24 GMT
content-location: Webmaster.html
vary: negotiate,Accept-Encoding
tcn: choice
last-modified: Wed, 20 Jan 2021 16:18:52 GMT
etag: "40c2-5b9574f94d300;5a7baed44d5a0"
accept-ranges: bytes
content-length: 16578
cache-control: max-age=21600
expires: Thu, 27 May 2021 14:07:24 GMT
content-type: text/html; charset=utf-8
x-backend: ssl-mirrors
strict-transport-security: max-age=15552000; includeSubdomains; preload
content-security-policy: upgrade-insecure-requests