安装编译环境及依赖，如部分软件不能安装请先安装epel源。
yum install pam-devel readline-devel http-parser-devel unbound gmp-devel
yum install tar gzip xz wget gcc make autoconf
ocserv编译安装依赖，ocserv需要gnutls3版本以上，gnutls依赖nettle2.7.1：
wget ftp://ftp.gnu.org/gnu/nettle/nettle-2.7.1.tar.gz
tar zxvf nettle-2.7.1.tar.gz
cd nettle-2.7.1/
./configure –prefix=/usr/local/nettle
make && make install
echo ‘/usr/local/nettle/lib64/’ > /etc/ld.so.conf.d/nettle.conf
ldconfig
安装gnutls3.3.9：
export NETTLE_CFLAGS=”-I/usr/local/nettle/include/”
export NETTLE_LIBS=”-L/usr/local/nettle/lib64/ -lnettle”
export HOGWEED_LIBS=”-L/usr/local/nettle/lib64/ -lhogweed”
export HOGWEED_CFLAGS=”-I/usr/local/nettle/include”
wget ftp://ftp.gnutls.org/gcrypt/gnutls/v3.3/gnutls-3.3.9.tar.xz
tar xvf gnutls-3.3.9.tar.xz
cd gnutls-3.3.9/
./configure –prefix=/usr/local/gnutls
make && make install
ln -s /usr/local/gnutls/bin/certtool /usr/bin/certtool
echo ‘/usr/local/gnutls/lib/’ > /etc/ld.so.conf.d/gnutls.conf
ldconfig
安装libnl：
yum install bison flex
wget http://www.carisma.slowglass.com/~tgr/libnl/files/libnl-3.2.24.tar.gz
tar xvf libnl-3.2.24.tar.gz
cd libnl-3.2.24
./configure –prefix=/usr/local/libnl
make && make install
echo ‘/usr/local/libnl/lib/’ > /etc/ld.so.conf.d/libnl.conf
ldconfig
安装ocserv：
export LIBNL3_CFLAGS=”-I/usr/local/libnl/include/libnl3″
export LIBNL3_LIBS=”-L//usr/local/libnl/lib/ -lnl-3 -lnl-route-3″
export LIBGNUTLS_LIBS=”-L/usr/local/gnutls/lib/ -lgnutls”
export LIBGNUTLS_CFLAGS=”-I/usr/local/gnutls/include/”
wget ftp://ftp.infradead.org/pub/ocserv/ocserv-0.9.0.1.tar.xz
tar xvf ocserv-0.9.0.1.tar.xz
cd ocserv-0.9.0
./configure –prefix=/usr/local/ocserv
make && make install
echo ‘export PATH=$PATH://usr/local/ocserv/sbin/:/usr/local/ocserv/bin/’ >> $HOME/.bashrc
source $HOME/.bashrc
生成SSL证书：
mkdir /etc/ocserv/
cd /etc/ocserv
#CA私钥：
certtool –generate-privkey –outfile ca-key.pem
#CA模板：
cat << EOF > ca.tmpl
cn = “thinkingandcreating.com”
organization = “thinkingandcreating.com”
serial = 1
expiration_days = 3650
ca
signing_key
cert_signing_key
crl_signing_key
EOF
#CA证书：
certtool –generate-self-signed –load-privkey ca-key.pem –template ca.tmpl –outfile ca-cert.pem
#Server私钥：
certtool –generate-privkey –outfile server-key.pem
#Server证书模板：
cat << EOF > server.tmpl
cn = “thinkingandcreating.com”
o = “thinkingandcreating.com”
expiration_days = 3650
signing_key
encryption_key
tls_www_server
EOF
#Server证书：
certtool –generate-certificate –load-privkey server-key.pem –load-ca-certificate ca-cert.pem –load-ca-privkey ca-key.pem –template server.tmpl –outfile server-cert.pem
密码登录，生成密码文件：
ocpasswd -c /etc/ocserv/passwd username
证书登录：
#user私钥
certtool –generate-privkey –outfile user-key.pem
#user模板
cat << EOF > user.tmpl
cn = “some random name”
unit = “some random unit”
expiration_days = 365
signing_key
tls_www_client
EOF
#user证书
certtool –generate-certificate –load-privkey user-key.pem –load-ca-certificate ca-cert.pem –load-ca-privkey ca-key.pem –template user.tmpl –outfile user-cert.pem
配置文件：
auth = “plain[/etc/ocserv/passwd]”
#证书认证
#auth = “certificate”
ca-cert /etc/ocserv/ca-cert.pem
max-clients = 16
max-same-clients = 2
tcp-port = 5551
udp-port = 5551
keepalive = 32400
try-mtu-discovery = true
cisco-client-compat = true
server-cert = /etc/ocserv/server-cert.pem
server-key = /etc/ocserv/server-key.pem
auth-timeout = 40
pid-file = /var/run/ocserv.pid
socket-file = /var/run/ocserv-socket
run-as-user = nobody
run-as-group = daemon
device = vpns
ipv4-network = 172.16.37.0
ipv4-netmask = 255.255.255.0
route = 172.16.37.0/255.255.255.0
启动opserv：
ocserv -f -c /etc/ocserv/ocserv.conf
IP转发及SNAT：
iptables -t nat -A POSTROUTING -j SNAT –to-source <服务器公网 IP > -o <对应网卡的名称>
iptables -t nat -A POSTROUTING -s 172.16.37.0/24 -o venet0 -j MASQUERADE
iptables -A FORWARD -s 172.16.37.0/24 -j ACCEPT
service iptables save
记得开始iptables
使用用户密码连接：
echo passwd|openconnect -u username thinkingandcreating.com:5551 –no-cert-check
使用证书连接：
openconnect -k user-key.pem -c user-cert.pem thinkingandcreating.com:5551 –no-cert-check