問題現象如下圖所示：

在開啟steam遊戲時出現了上述問題，無法正常遊戲。不光如此steam官網也無法正常顯示，只有部分文字和圖片，樣式缺失。

開啟chrome的F12開發者工具，進入network模組監視可發現大量的請求並沒有被響應，甚至沒有正常請求應有的狀態碼，但在request Headers中有一個警告資訊：Provisional headers are shown。

Provisional headers are shown 的大致意思是由於本機的原因（被遮蔽或者外掛的原因），該請求沒有實際上被髮送出去。在chrome://net-internals/ 中可檢視到

右側的資訊詳細如下

6053: URL_REQUEST
http://store.akamai.steamstatic.com/public/shared/javascript/jquery-1.8.3.min.js?v=.TZ2NKhB-nliU
Start Time: 2017-11-24 11:56:49.833

t=175962 [st=    0] +REQUEST_ALIVE  [dt=42013]
                     --> priority = "MEDIUM"
                     --> url = "http://store.akamai.steamstatic.com/public/shared/javascript/jquery-1.8.3.min.js?v=.TZ2NKhB-nliU"
 

t=175962 [st=    0]    URL_REQUEST_DELEGATE  [dt=0]
t=175962 [st=    0]   +URL_REQUEST_START_JOB  [dt=42012]
                       --> load_flags = 33024 (MAYBE_USER_GESTURE | VERIFY_EV_CERT)
                       --> method = "GET"
                       --> url = "http://store.akamai.steamstatic.com/public/shared/javascript/jquery-1.8.3.min.js?v=.TZ2NKhB-nliU"
 

t=175962 [st=    0]      URL_REQUEST_DELEGATE  [dt=0]
t=175963 [st=    1]      HTTP_CACHE_GET_BACKEND  [dt=0]
t=175963 [st=    1]      HTTP_CACHE_OPEN_ENTRY  [dt=2]
                         --> net_error = -2 (ERR_FAILED)
t=175965 [st=    3]      HTTP_CACHE_CREATE_ENTRY  [dt=5]
t=175970 [st=    8]      HTTP_CACHE_ADD_TO_ENTRY  [dt=0]
t=175971 [st=    9]     +HTTP_STREAM_REQUEST  [dt=42003]
t=175971 [st=    9]        HTTP_STREAM_JOB_CONTROLLER_BOUND
                           --> source_dependency = 6134 (HTTP_STREAM_JOB_CONTROLLER)
t=217974 [st=42012]        HTTP_STREAM_REQUEST_BOUND_TO_JOB
                           --> source_dependency = 6135 (HTTP_STREAM_JOB)
t=217974 [st=42012]     -HTTP_STREAM_REQUEST
t=217974 [st=42012]   -URL_REQUEST_START_JOB
                       --> net_error = -118 (ERR_CONNECTION_TIMED_OUT)
t=217974 [st=42012]    URL_REQUEST_DELEGATE  [dt=1]
t=217975 [st=42013] -REQUEST_ALIVE
                     --> net_error = -118 (ERR_CONNECTION_TIMED_OUT)

由於認識所限，這張表暫時看不懂，但很明顯這裡出現了問題（~。~）。

分析了一通，問題原因最終定位到hosts檔案上。由於本人的機子為了能翻牆訪問google，youtube等外網網站，更改了機子上的hosts檔案，新hosts檔案中有這樣一段：

## Steam
2600:1417:a:192::3a7 api.steampowered.com
2600:1417:a:192::3a7 support.steampowered.com
2600:1417:a::174c:cc5b repo.steampowered.com
2600:1417:a::174c:cc5b cdn.akamai.steamstatic.com
2600:1417:a::174c:cc5b store.akamai.steamstatic.com
2600:1417:a::174c:cc5b cdn.store.steampowered.com
2600:1417:a::174c:cc5b cdn.steampowered.com
2600:1417:a::174c:cc5b media.steampowered.com
2600:1417:a::174c:cc5b media4.steampowered.com
2600:1417:a::174c:cc5b content8.steampowered.com
2600:1417:a::174c:cc5b cloud-3.steampowered.com
2600:1417:a::174c:cc5b cloud-3.steamusercontent.com
2600:1417:a::174c:cc5b images.akamai.steamusercontent.com
2600:1417:a::174c:cc5b steamcdn-a.akamaihd.net
2600:1417:a::174c:cc5b steamstore-a.akamaihd.net
2600:1417:a::174c:cc5b steamcommunity-a.akamaihd.net
2600:1417:a::174c:cc5b cdn.steamcommunity.com
2600:1417:a::174c:cc5b store.valvesoftware.com

去掉即可（~。~）

以上，可以正常遊戲了，但原因並沒有完全弄明白，本文待續。