用wget下載一個圖片資源（https協議），在服務器上可以，但在本機的虛擬機中卡在下面這里了:

[root@localhost ~]# wget 'https://gp1.wac.edgecastcdn.net/806614/photos/photos.500px.net/90241693/795b7a5900db5905631ebe7ff5aa141a5e0f59ce/3.jpg?v=6'--2014-11-21 09:33:17--  https://gp1.wac.edgecastcdn.net/806614/photos/photos.500px.net/90241693/795b7a5900db5905631ebe7ff5aa141a5e0f59ce/3.jpg?v=6Resolving gp1.wac.edgecastcdn.net... 159.106.121.75, 37.61.54.158Connecting to gp1.wac.edgecastcdn.net|159.106.121.75|:443... failed: Connection timed out.Connecting to gp1.wac.edgecastcdn.net|37.61.54.158|:443... connected.

最后發現是DNS的問題，把域名改為ip就可以了。