IPsec PPTP L2TP ???

???? (Tunneling)???????????????????????????????????????????(Encapsulation)??????????????????????????????????IPsec?PPTP ? L2TP ????

PPTP ? L2TP ??????????????? IP/IPX/AppleTalk ?????????IPsec?PPTP?L2TP ???????????? IPsec ????????????? Internet ? VPN ??????? (?? Internet/Intranet/Extranet/Remote Access...?)?? PPTP ? L2TP ??????? VPN ?????????? Internet ???????????????????IPSec ???????????? PPTP ? L2TP ?????????? (Encapsulation) ???????????????????

?????????

???????????????????????????????????VPN ?? PPTP ?????? (???????) ??? IP ???????????????????(PPTP)????????????(L2TP) ??????????????(SSTP) ???? VPN ?????

PPTP?L2TP ? SSTP ?????????????????????(PPTP) ????PPP ????????????????????????? IP?PPP ? IP ????? PPP ?????????????????? PPP ???PPP ??????????????????????????????

PPTP

PPTP ?????????????????? IP ??????? IP ????? IP ?? (???????) ???PPTP ??????????? VPN ???????????? VPN ???????PPTP ?????? PPTP ? VPN ????????????????????????????

??

PPTP ? PPP ????? IP ?????????????PPTP ?? TCP ???????????? Generic Routing Encapsulation (GRE) ???????????? PPP ?????? PPP ?????????????????????????? IP ???? PPTP ??????

?? IP ???? PPTP ?????

??

PPP ???? MS-CHAP v2 ? EAP-TLS ?????????????? Microsoft ????? (MPPE) ????????????????? MS-CHAP v2 ? EAP-TLS ???????????? PPP ??????PPTP ???? PPP ??????????? PPP ???

L2TP

L2TP ???????????????????????????????? (???IP ???????? (ATM)) ????L2TP ? PPTP ????????(L2F) ?????? Cisco Systems, Inc. ???????L2TP ??? PPTP ? L2F ??????

? PPTP ???Microsoft ???? L2TP ??? MPPE ??? PPP ????L2TP ???????????????????????(IPsec) ????????L2TP ? IPsec ?????? L2TP/IPsec?

VPN ???? VPN ???????? L2TP ? IPsec?L2TP ????????? Windows Vista® ? Windows XP ????????? L2TP ? VPN ???????? Windows Server® 2008 ? Windows Server 2003 ???????

L2TP ??? TCP/IP ????????

??

L2TP/IPsec ????????????

????L2TP ??

? PPP ?? (IP ???) ??? L2TP ??? UDP ???

?? IP ???? L2TP ?????

????IPsec ??

????? L2TP ????? IPsec????????(ESP) ????????????????? IPsec ?????????? IP ???? IP ???????? VPN ???? VPN ?????????? IP ???

? IPsec ESP ?? L2TP ??

??

L2TP ???????????????(IKE) ?????????????????????(DES) ???????????(3DES) ?????

SSTP

?????????????(SSTP) ???????????? TCP ??? 443 ?? HTTPS ????????????????? PPTP ? L2TP/IPsec ????????? Proxy?SSTP ???? HTTPS ?????????????(SSL) ????? PPP ???????? PPP ??????????? EAP-TLS?SSL ???????????????????????????

????????? SSTP ???? VPN ????SSTP ????? SSTP ?????? HTTPS ????? HTTPS ???????????????????

??

SSTP ? PPP ????? IP ?????????????SSTP ?? TCP ?? (????? 443) ????????? PPP ???????

??

SSTP ???? HTTPS ????? SSL ???????

????????

???? PPTP?L2TP/IPsec ? SSTP ???? VPN ??????????????????

?? Microsoft ??????? PPTP??? Microsoft Windows 2000?Windows XP?Windows Vista ?? Windows Server 2008?? L2TP/IPsec ???PPTP ????????????? (PKI)????????? PPTP ???? VPN ?????????? (????????????????)????? PPTP ???? VPN ?????????? (?????????????) ??????? (???????????????)?
L2TP ?????? Windows 2000?Windows XP ? Windows Vista ?????????L2TP ??????????????? IPsec ???????????? (???????) ???? PKI ???????? VPN ???????? VPN ?????????? IPsec?L2TP/IPsec VPN ??????????????????????

? PPTP ? SSTP ???L2TP/IPsec ? IPsec ?????????? PPP ???????????
SSTP ?????? Windows Vista Service Pack 1 (SP1) ? Windows Server 2008 ????????????? SSL?SSTP VPN ??????????????????????
???????? PPP ?????????????????????PPP ????? (????????????????? (IPv4)?????????? (IPV6) ??????????? (NAP)) ????????????

??????

PPTP ??? IETF RFC ???? RFC 2637 ?? (???????)
L2TP ??? IETF RFC ???? RFC 2661 ?? (???????)
L2TP/IPsec ??? IETF RFC ???? RFC 3193 ?? (???????)