Depois que reiniciei o VPS do EC2 Management Console, o VPS recebeu outro novo ip público, então o problema foi resolvido. Isso é muito estranho. Eu acho que isso está relacionado com a complicada configuração de rede da AWS.
Eu configurei um VPN server on AWS Ubuntu 14.04.1 LTS VPS . E adicionei NAT no servidor para meu Win7 client PC . Depois de me conectar a esse VPN , não consigo acessar nenhum site. Mas eu posso pingar google.com do meu Win7 client PC . E o nslookup funciona bem quando eu estava digitando nslookup google.com .
Eu fiz as etapas a seguir para VPN and NAT setup :
Pacotes necessários instalados
sudo aptitude install ppp pptpd iptables
Configurado PPTP IP ranges no servidor
sudo vim /etc/pptpd.conf
localip 192.168.100.1
remoteip 192.168.100.1-199
Configurado DNS servers para usar quando os clientes se conectarem a este PPTP server
sudo vim /etc/ppp/pptpd-options
ms-dns 8.8.8.8
ms-dns 8.8.4.4
Adicionada uma conta de teste
sudo vim /etc/ppp/chap-secrets
# client server secret IP addresses
test pptpd abcd1234 *
Adicionado iptables rule
sudo vim /etc/rc.local
sudo iptables -t nat -A POSTROUTING -s 192.168.100.0/24 -j MASQUERADE
Ativado IPv4 forwading
sudo vim /etc/sysctl.conf
net.ipv4.ip_forward=1
Recarregou a configuração
sudo sysctl -p
Reiniciou o servidor
sudo reboot
Aqui estão os registros para PPTPD e PPPD quando a conexão VPN estabelece:
Dec 26 02:20:45 ip-172-31-14-72 pptpd[1225]: CTRL: Client 183.62.136.251 control connection started
Dec 26 02:20:45 ip-172-31-14-72 pptpd[1225]: CTRL: Starting call (launching pppd, opening GRE)
Dec 26 02:20:45 ip-172-31-14-72 pppd[1226]: Plugin /usr/lib/pptpd/pptpd-logwtmp.so loaded.
Dec 26 02:20:45 ip-172-31-14-72 pppd[1226]: pptpd-logwtmp: $Version$
Dec 26 02:20:45 ip-172-31-14-72 pppd[1226]: pppd 2.4.5 started by root, uid 0
Dec 26 02:20:45 ip-172-31-14-72 pppd[1226]: using channel 1
Dec 26 02:20:45 ip-172-31-14-72 pppd[1226]: Using interface ppp0
Dec 26 02:20:45 ip-172-31-14-72 pppd[1226]: Connect: ppp0 <--> /dev/pts/1
Dec 26 02:20:45 ip-172-31-14-72 pppd[1226]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth chap MS-v2> <magic 0x893bee97> <pcomp> <accomp>]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: rcvd [LCP ConfReq id=0x0 <mru 1400> <magic 0x79ad5454> <pcomp> <accomp> <callback CBCP>]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: sent [LCP ConfRej id=0x0 <callback CBCP>]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <auth chap MS-v2> <magic 0x893bee97> <pcomp> <accomp>]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: rcvd [LCP ConfReq id=0x1 <mru 1400> <magic 0x79ad5454> <pcomp> <accomp>]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: sent [LCP ConfAck id=0x1 <mru 1400> <magic 0x79ad5454> <pcomp> <accomp>]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: sent [LCP EchoReq id=0x0 magic=0x893bee97]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: sent [CHAP Challenge id=0x75 <a27aa8aa1ca5bb9e4f326ff8ea59b781>, name = "pptpd"]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: rcvd [LCP Ident id=0x2 magic=0x79ad5454 "MSRASV5.20"]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: rcvd [LCP Ident id=0x3 magic=0x79ad5454 "MSRAS-0-PC201404170414"]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: rcvd [LCP Ident id=0x4 magic=0x79ad5454 "0w7777777774777777607777777651777777676H777777667777777737sudo aptitude install ppp pptpd iptables
67777776657777777777777777652777777655"]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: rcvd [LCP EchoRep id=0x0 magic=0x79ad5454]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: rcvd [CHAP Response id=0x75 <0a403b0e014f3edabcf7ae41b863f2ad0000000000000000cfe4bbbd236c21274289fc6a6db9383acad0868e955e08f900>, name = "mtc"]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: sent [CHAP Success id=0x75 "S=B4CF7D2F19305CFC72BE10F163487851E9DE8F80 M=Access granted"]
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: peer from calling number 183.62.136.251 authorized
Dec 26 02:20:46 ip-172-31-14-72 pppd[1226]: sent [CCP ConfReq id=0x1 <mppe +H -M +S -L -D -C>]
Dec 26 02:20:46 ip-172-31-14-72 kernel: [7682099.701630] PPP MPPE Compression module registered
Dec 26 02:20:47 ip-172-31-14-72 pppd[1226]: rcvd [IPV6CP ConfReq id=0x5 <addr fe80::50b0:7670:15ae:d6f4>]
Dec 26 02:20:47 ip-172-31-14-72 pppd[1226]: Unsupported protocol 'IPv6 Control Protocol' (0x8057) received
Dec 26 02:20:47 ip-172-31-14-72 pppd[1226]: sent [LCP ProtRej id=0x2 80 57 01 05 00 0e 01 0a 50 b0 76 70 15 ae d6 f4]
Dec 26 02:20:47 ip-172-31-14-72 pppd[1226]: rcvd [CCP ConfReq id=0x6 <mppe +H -M +S -L -D -C>]
Dec 26 02:20:47 ip-172-31-14-72 pppd[1226]: sent [CCP ConfAck id=0x6 <mppe +H -M +S -L -D -C>]
Dec 26 02:20:47 ip-172-31-14-72 pppd[1226]: rcvd [IPCP ConfReq id=0x7 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-wins 0.0.0.0> <ms-dns2 0.0.0.0> <ms-wins 0.0.0.0>]
Dec 26 02:20:47 ip-172-31-14-72 pppd[1226]: sent [IPCP TermAck id=0x7]
Dec 26 02:20:47 ip-172-31-14-72 pppd[1226]: rcvd [CCP ConfAck id=0x1 <mppe +H -M +S -L -D -C>]
Dec 26 02:20:47 ip-172-31-14-72 pppd[1226]: MPPE 128-bit stateless compression enabled
Dec 26 02:20:47 ip-172-31-14-72 pppd[1226]: sent [IPCP ConfReq id=0x1 <addr 192.168.100.1>]
Dec 26 02:20:47 ip-172-31-14-72 pppd[1226]: rcvd [IPCP ConfAck id=0x1 <addr 192.168.100.1>]
Dec 26 02:20:48 ip-172-31-14-72 pppd[1226]: rcvd [IPCP ConfReq id=0x8 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-wins 0.0.0.0> <ms-dns2 0.0.0.0> <ms-wins 0.0.0.0>]
Dec 26 02:20:48 ip-172-31-14-72 pppd[1226]: sent [IPCP ConfRej id=0x8 <ms-wins 0.0.0.0> <ms-wins 0.0.0.0>]
Dec 26 02:20:48 ip-172-31-14-72 pppd[1226]: rcvd [IPCP ConfReq id=0x9 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Dec 26 02:20:48 ip-172-31-14-72 pppd[1226]: sent [IPCP ConfNak id=0x9 <addr 192.168.100.100> <ms-dns1 8.8.8.8> <ms-dns2 8.8.4.4>]
Dec 26 02:20:49 ip-172-31-14-72 pppd[1226]: rcvd [IPCP ConfReq id=0xa <addr 192.168.100.100> <ms-dns1 8.8.8.8> <ms-dns2 8.8.4.4>]
Dec 26 02:20:49 ip-172-31-14-72 pppd[1226]: sent [IPCP ConfAck id=0xa <addr 192.168.100.100> <ms-dns1 8.8.8.8> <ms-dns2 8.8.4.4>]
Dec 26 02:20:49 ip-172-31-14-72 pppd[1226]: Cannot determine ethernet address for proxy ARP
Dec 26 02:20:49 ip-172-31-14-72 pppd[1226]: local IP address 192.168.100.1
Dec 26 02:20:49 ip-172-31-14-72 pppd[1226]: remote IP address 192.168.100.100
Dec 26 02:20:49 ip-172-31-14-72 pppd[1226]: pptpd-logwtmp.so ip-up ppp0 mtc 183.62.136.251
Dec 26 02:20:49 ip-172-31-14-72 pppd[1226]: Script /etc/ppp/ip-up started (pid 1252)
Dec 26 02:20:49 ip-172-31-14-72 pppd[1226]: Script /etc/ppp/ip-up finished (pid 1252), status = 0x0