mac使用pptp的正確方式

環境：macos mojave 10.14.6

嘗試的解決方案：

1. mac自帶vpn 結論：已經不支持pptp協議

2. 使用shimo 結論：無用，連接的時候沒反應

3. 為了解決不能連接的問題，某老外寫的pptp連接工具 結論：無用，報錯信息和下一步腳本執行結果一樣

4. 實用pppd，步驟如下：

   1）進入 /etc/ppp/peers/ 目錄，創建 test.vpn，此文件名自己取；

   2）寫入以下內容，根據需要修改；

   plugin PPTP.ppp
   noauth
   remoteaddress "------VPN server name or IP address------"
   user "------VPN username------"
   password "------VPN password------"
   redialcount 1
   redialtimer 5
   idle 1800
   # mru 1368
   # mtu 1368
   receive-all
   novj 0:0
   ipcp-accept-local
   ipcp-accept-remote
   refuse-eap
   refuse-pap
   refuse-chap-md5
   hide-password
   mppe-stateless
   mppe-128
   # require-mppe-128
   looplocal
   nodetach
   ms-dns 8.8.8.8
   usepeerdns
   # ipparam gwvpn
   defaultroute
   debug
   

   3）運行sudo pppd call test.vpn

   結論：出錯，結果如下：

   Sat Feb 29 11:24:47 2020 : publish_entry SCDSet() failed: Success!
   Sat Feb 29 11:24:47 2020 : publish_entry SCDSet() failed: Success!
   Sat Feb 29 11:24:47 2020 : PPTP connecting to server 'xxx.xxx.xxx.xxx' (xxx.xxx.xxx.xxx)...
   Sat Feb 29 11:24:48 2020 : PPTP connection established.
   Sat Feb 29 11:24:48 2020 : PPTP set port-mapping for en0, interface: 9, protocol: 0, privatePort: 0
   Sat Feb 29 11:24:48 2020 : using link 0
   Sat Feb 29 11:24:48 2020 : Using interface ppp0
   Sat Feb 29 11:24:48 2020 : Connect: ppp0 <--> socket[34:17]
   Sat Feb 29 11:24:48 2020 : sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x60725c7f> ]
   Sat Feb 29 11:24:51 2020 : rcvd [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x90775e6> ]
   Sat Feb 29 11:24:51 2020 : lcp_reqci: returning CONFACK.
   Sat Feb 29 11:24:51 2020 : sent [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x90775e6> ]
   Sat Feb 29 11:24:51 2020 : sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x60725c7f> ]
   Sat Feb 29 11:24:51 2020 : rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x60725c7f> ]
   Sat Feb 29 11:24:51 2020 : rcvd [CHAP Challenge id=0xf9 <4a44a223bded3c174d9524e514b7b186>, name = "pptpd"]
   Sat Feb 29 11:24:51 2020 : sent [CHAP Response id=0xf9 <7fa23ba608c73e19030ab3ac356541de00000000000044442b41d5fa9f4034e4ba1cf873502c4e3e4ca4d86752c1994800>, name = "xx"]
   Sat Feb 29 11:24:51 2020 : rcvd [LCP ConfReq id=0x2 <asyncmap 0x0> <magic 0x241bc6d7> ]
   Sat Feb 29 11:24:51 2020 : sent [LCP ConfReq id=0x2 <asyncmap 0x0> <magic 0x330e8a78> ]
   Sat Feb 29 11:24:51 2020 : lcp_reqci: returning CONFACK.
   Sat Feb 29 11:24:51 2020 : sent [LCP ConfAck id=0x2 <asyncmap 0x0> <magic 0x241bc6d7> ]
   Sat Feb 29 11:24:51 2020 : rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x60725c7f> ]
   Sat Feb 29 11:24:51 2020 : rcvd [LCP ConfAck id=0x2 <asyncmap 0x0> <magic 0x330e8a78> ]
   Sat Feb 29 11:24:51 2020 : rcvd [CHAP Challenge id=0xf1 <7152e60444448f03c00d77bc4f4f85e7>, name = "pptpd"]
   Sat Feb 29 11:24:51 2020 : sent [CHAP Response id=0xf1 <67c6ba6d36b2fcf0f07d2b24d38a13db000000000000000099b744446dee24113587aab45c859bc033099f424d94e50400>, name = "xx"]
   Sat Feb 29 11:24:51 2020 : rcvd [CHAP Success id=0xf1 "S=21E481AFF77DB980039418F738D7749C6A4C590A M=Access granted"]
   Sat Feb 29 11:24:51 2020 : sent [CCP ConfReq id=0x1 <mppe +H -M +S -L -D -C>]
   Sat Feb 29 11:24:51 2020 : rcvd [CCP ConfReq id=0x1 <deflate 15> <deflate(old#) 15>]
   Sat Feb 29 11:24:51 2020 : MPPE required but peer negotiation failed
   Sat Feb 29 11:24:51 2020 : sent [LCP TermReq id=0x3 "MPPE required but peer negotiation failed"]
   Sat Feb 29 11:24:51 2020 : Connection terminated.
   Sat Feb 29 11:24:51 2020 : sent [CCP ConfRej id=0x1 <deflate 15> <deflate(old#) 15>]
   Sat Feb 29 11:24:51 2020 : PPTP disconnecting...
   Sat Feb 29 11:24:51 2020 : PPTP clearing port-mapping for en0
   Sat Feb 29 11:24:51 2020 : PPTP disconnected

   可以發現，報錯信息在這里：

   MPPE required but peer negotiation failed

   多方搜索無果，只能靠自己了......

   再次打開 test.vpn 配置文件，我發現了其中關於 mmpe 的部分：

   mppe-stateless
   mppe-128
   # require-mppe-128
   

   發現問題所在了嗎？我搜索到的所有教我配置pppd配置文件中的內容都是這樣，但是報錯卻提示“MPPE required but peer negotiation failed”，因此，我嘗試將另外兩行和mmpe相關的配置行注釋掉，結果如下：

   # mppe-stateless
   # mppe-128
   # require-mppe-128
   

   再次執行 sudo pppd call test.vpn，錯誤解決，運行成功！！

   如圖，運行成功后，最下面兩行是這樣：