install openvpn on amazon ec2

Jan 13, 201212

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This article provides instructions on how to install and configure OpenVPN on an Amazon EC2 instance. It includes steps for updating and installing OpenVPN, generating keys, configuring server and client files, and setting up iptables. The article also suggests using tcpdump to monitor data packets.

1 yum update

yum install openvpn

2 openvpn —genkey —secret /etc/openvpn/openvpn-key.txt

#--- server.conf
port 1194
proto udp
dev tun
secret openvpn-key.txt
ifconfig 192.168.2.1 192.168.2.2
keepalive 10 120
comp-lzo
persist-key
persist-tun
status server-tcp.log
verb 3

#----client.conf
dev tun
proto udp
remote INSERT-YOUR-COMPLETE-PUBLIC-EC2-HOSTNAME-HERE 1194
resolv-retry infinite
nobind
secret openvpn-key.txt
ifconfig 192.168.2.2 192.168.2.1
comp-lzo
verb 3
dhcp-option DNS 172.16.0.23
redirect-gateway def1

service restart openvpn 启动后就可以连接上了，这个 openvpn-key.txt 在服务端和客户端都要有。
3 连接上了，但是还不能访问其他地址的网站，要配置 iptables （我测试了，我的 ec2 不行，其他老外的可以，再试试） /etc/sysconfig/iptables 文件内容：
#-----------
*nat
ACCEPT [0:0]
ACCEPT [0:0]
ACCEPT [0:0]
-A POSTROUTING -s 192.168.2.0/24 -d 0.0.0.0/0 -o eth0 -j MASQUERADE
COMMIT
4 在文件 /etc/init.d/openvpn 中
把 #echo 1 /proc/sys/net/ipv4/ip_forward
改成 echo 1 /proc/sys/net/ipv4/ip_forward
service openvpn restart chkconfig openvpn on 连接上去试试就知道能不能用了，可以用 tcpdump dst port 80 or src port 80 查看数据包

参考：
1 http://holgr.com/blog/2009/06/setting-up-openvpn-on-amazons-ec2/