返回：
\u0026lt;html\u0026gt;\u0026lt;head\u0026gt;\u0026lt;title\u0026gt;400 Bad Request\u0026lt;/title\u0026gt;\u0026lt;/head\u0026gt;\u0026lt;body bgcolor="white"\u0026gt;\u0026lt;center\u0026gt;\u0026lt;h1\u0026gt;400 Bad Request\u0026lt;/h1\u0026gt;\u0026lt;/center\u0026gt;\u0026lt;hr\u0026gt;\u0026lt;center\u0026gt;nginx\u0026lt;/center\u0026gt;\u0026lt;/body\u0026gt;\u0026lt;/html\u0026gt;目前并不知道原因，根据一些经验，我猜测是由于http请求头Host值的问题，于是我将host手动调整为http://www.zhihu.com，成功得到了官网的响应，验证了我的猜想。
请求网址：https://118.89.204.192/GET / HTTP/1.1Host: www.zhihu.comUser-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:66.0) Gecko/20100101 Firefox/66.0Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2Accept-Encoding: gzip, deflate, brConnection: keep-aliveCookie: _zap=af8e0c0c-435b-483c-ab4d-fb86ca8e6020; d_c0="AKAjpcslDg-PTuwgw-S-BSlU8YrYwjf9w64=|1551427469"; _xsrf=asOXc1EYwWCKRRPBSJoKqtK04fOfM8uz; capsion_ticket="2|1:0|10:1556453804|14:capsion_ticket|44:MDk4ODkxMWRiNTBlNDIwZmEwNTEzZjEzMjE5MTE0MzE=|ac1435b4f3b476d99007334812e038c58280c2d7de03e1827a1fba2d4c3b2799"; r_cap_id="MjljMGVlNGU0ZDY5NDdkZTk2NjFiNzZiMTRkYjZiNTc=|1556453807|d3f0afd0b437c15a58c4de27ef4cc78b307424d4"; cap_id="Y2Q4MmZlOTgxMDMwNGExYmI0Mzc5OGJiODQyY2JjNmY=|1556453807|5176a3d85806ac3c6f9c8d9104ad6029c4575d69"; l_cap_id="MzZkNWQzNGViMjBkNGM0OGFjMDNkMTA5NTQ3ODcwMDQ=|1556453807|7864c71feebc6ee83596297404c115b19eec037d"; z_c0=Mi4xYXdLTEFnQUFBQUFBb0NPbHl5VU9EeGNBQUFCaEFsVk52dWV5WFFDbzEyQ0llT1dnMEY3UDFEUExmYldWMTUxSHRB|1556453822|a054a74c7d0cb75a88dceec93da46746143c32de; tst=r; q_c1=5271c2958b1c412fa9a9e0b5b50604c9|1556453828000|1556453828000; __gads=ID=2d9cb482a8f15c3e:T=1556453831:S=ALNI_MZXP7BURulhpZ0JBDM1NOcuzdDVkg; tgw_l7_route=66cb16bc7f45da64562a077714739c11Upgrade-Insecure-Requests: 1Cache-Control: max-age=0, no-cacheTE: TrailersPragma: no-cache响应：
HTTP/2.0 200 OKdate: Sun, 28 Apr 2019 13:17:06 GMTcontent-type: text/html; charset=utf-8vary: Accept-Encodingset-cookie: tst=; path=/; expires=Thu, 01 Jan 1970 00:00:00 GMT; httponlycontent-security-policy: default-src * blob:; img-src * data: blob:; connect-src * wss: blob:; frame-src \u0026#39;self\u0026#39; *.zhihu.com weixin: *.vzuu.com getpocket.com note.youdao.com safari-extension://com.evernote.safari.clipper-Q79WDW8YH9 zhihujs: captcha.guard.qcloud.com; script-src \u0026#39;self\u0026#39; blob: *.zhihu.com res.wx.qq.com \u0026#39;unsafe-eval\u0026#39; unpkg.zhimg.com unicom.zhimg.com captcha.gtimg.com captcha.guard.qcloud.com pagead2.googlesyndication.com i.hao61.net \u0026#39;nonce-5477d401-e67f-41f4-8f96-6c2cd02429c8\u0026#39;; style-src \u0026#39;self\u0026#39; \u0026#39;unsafe-inline\u0026#39; *.zhihu.com unicom.zhimg.com captcha.gtimg.comx-frame-options: SAMEORIGINstrict-transport-security: max-age=15552000; includeSubDomainssurrogate-control: no-storecache-control: no-store, no-cache, must-revalidate, proxy-revalidatepragma: no-cacheexpires: 0x-content-type-options: nosniffx-xss-protection: 1; mode=blockx-backend-response: 0.338content-encoding: brserver: ZWSX-Firefox-Spdy: h2