trouble shooting 问题跟踪

在家里经常会搜一些技术文档，但是很多技术文档都是在简书上的。而家里的网络无法打开简书。今天彻底跟进下、看具体什么问题造成的无法打开？当然浏览器下是无法打开的。浏览器下的打开报错如下

怀疑过DNS解析的问题，所以先修改了DNS分别去访问，还是问题依然所以首先尝试命令行下访问测试：

➜ ~ curl -I http://www.jianshu.com

HTTP/1.1 301 Moved Permanently

Date: Tue, 20 Oct 2020 12:44:51 GMT

Content-Type: text/html

Content-Length: 278

Connection: keep-alive

Location: https://www.jianshu.com/

从上面结果来看是默认跳转到https的，这次访问https页面测试、他是报错无法打开。

➜ ~ curl -I https://www.jianshu.com

curl: (35) LibreSSL SSL_connect: SSL_ERROR_SYSCALL in connection to www.jianshu.com:443

查看客户端到服务器之间的网络情况。也没有问题，都是OK的

➜ ~ ping -c 5 www.jianshu.com

PING www.jianshu.com (47.92.108.93): 56 data bytes

64 bytes from 47.92.108.93: icmp_seq=0 ttl=51 time=36.588 ms

64 bytes from 47.92.108.93: icmp_seq=1 ttl=51 time=36.466 ms

64 bytes from 47.92.108.93: icmp_seq=2 ttl=51 time=32.454 ms

64 bytes from 47.92.108.93: icmp_seq=3 ttl=51 time=36.610 ms

64 bytes from 47.92.108.93: icmp_seq=4 ttl=51 time=36.272 ms

--- www.jianshu.com ping statistics ---

5 packets transmitted, 5 packets received, 0.0% packet loss

round-trip min/avg/max/stddev = 32.454/35.678/36.610/1.616 ms

对获取的IP进行探测：

➜ ~ sudo nmap -sT 47.92.108.93

Starting Nmap 7.91 ( https://nmap.org ) at 2020-10-20 20:47 CST

Nmap scan report for 47.92.108.93

Host is up (0.034s latency).

Not shown: 998 filtered ports

PORT STATE SERVICE

80/tcp open http

443/tcp open https

也就是开放了80和443端口

再看下客户端到服务器之间的路由路径。

sudo mtr 47.92.108.93 |nali

sudo mtr www.jianshu.com

IPv6？？

➜ ~ sudo mtr www.baidu.com 这个域名可以正常解析。

难道是不支持IPv6？

查看下我的Wi-Fi配置，我的本地IP地址自动获取到了IPV6的地址。

直接可以这里关闭，或者

networksetup -setv6off Wi-Fi

操作之后再次测试

➜ ~ curl -I https://www.jianshu.com

HTTP/1.1 200 OK

Server: Tengine

Date: Tue, 20 Oct 2020 13:08:01 GMT

Content-Type: text/html; charset=utf-8

Connection: keep-alive

Vary: Accept-Encoding

X-Frame-Options: SAMEORIGIN

X-XSS-Protection: 1; mode=block

X-Content-Type-Options: nosniff

ETag: W/"65f7c787bb0157e53cc028949950c5a5"

Cache-Control: max-age=0, private, must-revalidate

Set-Cookie: locale=zh-CN; path=/

X-Request-Id: 6dd8b96d-331e-4d1a-a8e3-57b2ec830021

X-Runtime: 0.003816

Strict-Transport-Security: max-age=31536000; includeSubDomains; preload

搞定。究其原因原来是IPV6造成的。