I met the problem: Mac VPN PPTP Connects but doesn't work . Even if I modified routing table, still doesn't work. 遇到如 Mac VPN PPTP Connects but doesn't work 相同的情形，Mac撥號pptp server成功，但怎麼樣都ping不到，明顯是不知哪個環節錯了，手動改routing table也沒用。 I backup and erase the contents of /Library/Preferences/SystemConfiguration , then after a restart I have to reset network and VPN worked again. 我照討論區裏將 /Library/Preferences/SystemConfiguration 裏的檔案備份並刪除，重開之後重新設定網路，VPN就正常運作。 But you have to notice, remove these configuration files will influence many thins. 必須要注意刪除這些設定檔將會影響許多東西，請小心。 Update: 據強者表示，刪/Library/Preferences/SystemConfiguration下的com.apple.airport.preferences.plist、com.apple.nat.plist、com.apple.network.identification.plist就夠了，需要的朋友可以試看看。