在 CentOS 7 中使用 strongSwan 搭建 IKEv2 VPN

本文介绍在 CentOS 7 系统中使用 strongSwan 开源软件搭建 IKEv2 方式的 VPN 配置。

本文涉及到的各项系统及软件版本：

• 服务端系统：CentOS 7.4 64位
• 客户端系统：Windows 10 专业版，版本号 1809
• 软件：strongSwan 版本 5.7.2

一、安装 strongSwan

使用 EPEL 源安装 strongSwan，因为 EPEL 包含 strongSwan 最新版本，EPEL 更新比较快，如果系统中没有，则执行下面命令安装 EPEL 源。

1、安装 EPEL 源

yum -y install epel-release

注意，这不是必须的，你也可以使用其它源安装。

2、安装 openssl

yum -y install openssl

注意，这不是必须的，请根据实际情况调整。

3、安装 strongswan

yum -y install strongswan

注意，这是必须的。

4、设置开机启动

systemctl enable strongswan

二、创建证书

1、创建 CA 根证书

1.1 创建一个私钥：

strongswan pki --gen --outform pem > ca.key.pem

1.2 基于这个私钥自己签一个 CA 根证书：

strongswan pki --self --in ca.key.pem --dn "C=CN, O=123si, CN=123si StrongSwan CA" --ca --lifetime 3650 --outform pem > ca.cert.pem

命令参数介绍：

2、创建服务器端证书

2.1 创建一个私钥：

strongswan pki --gen --outform pem > server.key.pem

2.2 用我们刚才自签的 CA 证书给自己发一个服务器证书：

# 用私钥创建公钥
strongswan pki --pub --in server.key.pem --outform pem > server.pub.pem
# 用刚创建的公钥，创建服务器证书
strongswan pki --issue --lifetime 3650 --cacert ca.cert.pem --cakey ca.key.pem --in server.pub.pem --dn "C=CN, O=123si, CN=48.85.166.86" --san="48.85.166.86" --flag serverAuth --flag ikeIntermediate --outform pem > server.cert.pem

命令参数介绍：

--issue，--cacert和--cakey就是表明要用刚才自签的 CA 证书来签这个服务器证书。

--dn，--san，--flag是一些客户端方面的特殊要求：

• iOS 客户端要求 CN 也就是通用名必须是你的服务器的 URL 或 IP 地址；
• Windows 7 不但要求了上面，还要求必须显式说明这个服务器证书的用途（用于与服务器进行认证），--flag serverAuth；
• 非 iOS 的 Mac OS X 要求了“IP 安全网络密钥互换居间（IP Security IKE Intermediate）”这种增强型密钥用法（EKU），--flag ikdeIntermediate；
• Android 和 iOS 都要求服务器别名（serverAltName）就是服务器的 URL 或 IP 地址，--san；

3、创建客户端证书

3.1 创建一个私钥：

strongswan pki --gen --outform pem > client.key.pem

3.2 然后用刚才自签的 CA 证书来签客户端证书：

# 用私钥创建公钥
strongswan pki --pub --in client.key.pem --outform pem > client.pub.pem
# 用刚创建的公钥，创建客户端证书
strongswan pki --issue --lifetime 3650 --cacert ca.cert.pem --cakey ca.key.pem --in client.pub.pem --dn "C=CN, O=123si, CN=48.85.166.86" --outform pem > client.cert.pem

4、打包证书为 pkcs12

openssl pkcs12 -export -inkey client.key.pem -in client.cert.pem -name "123si StrongSwan Client Cert" -certfile ca.cert.pem -caname "123si StrongSwan CA" -out client.cert.p12

执行命令后，会提示输入两次密码，这个密码是在导入证书到其他系统时需要验证的。没有这个密码即使别人拿到了证书也没法使用。

三、安装证书

cp -r ca.key.pem /etc/strongswan/ipsec.d/private/
cp -r ca.cert.pem /etc/strongswan/ipsec.d/cacerts/
cp -r server.cert.pem /etc/strongswan/ipsec.d/certs/
cp -r server.pub.pem /etc/strongswan/ipsec.d/certs/
cp -r server.key.pem /etc/strongswan/ipsec.d/private/
cp -r client.cert.pem /etc/strongswan/ipsec.d/certs/
cp -r client.key.pem /etc/strongswan/ipsec.d/private/

把 CA 证书（ca.cert.pem）、客户端证书（client.cert.pem）和 .p12 证书（client.cert.p12）用 FTP 复制出来给客户端用。

四、配置 VPN

1、修改主配置文件 ipsec.conf

配置文件ipsec.conf官方介绍链接：ipsec.conf: conn Reference

编辑配置文件：

vim /etc/strongswan/ipsec.conf

配置文件常用设置说明：

config setup
    # 是否缓存证书吊销列表
    # <em>cachecrls = yes</em>
    # 是否严格执行证书吊销规则
    # strictcrlpolicy=yes
    # 如果同一个用户在不同的设备上重复登录，yes 断开旧连接，创建新连接；no 保持旧连接，并发送通知；never 同 no，但不发送通知。
    uniqueids=no
# 配置根证书，如果不使用证书吊销列表，可以不用这段。命名为 %default 所有配置节都会继承它
# ca %default
    # 证书吊销列表 URL，可以是 LDAP，HTTP，或文件路径
    # crluri = <uri>
# 定义连接项，命名为 %default 所有连接都会继承它
conn %default
    # 是否启用压缩，yes 表示如果支持压缩会启用
    compress = yes
    # 当意外断开后尝试的操作，hold，保持并重连直到超时
    dpdaction = hold
    # 意外断开后尝试重连时长
    dpddelay = 30s
    # 意外断开后超时时长，只对 IKEv1 起作用
    dpdtimeout = 60s
    # 闲置时长，超过后断开连接
    inactivity = 300s
    # 数据传输协议加密算法列表
    esp = aes256-sha256,aes256-sha1,3des-sha1!
    # 密钥交换协议加密算法列表
    ike = aes256-sha1-modp1024,aes128-sha1-modp1024,3des-sha1-modp1024!
    # 默认的密钥交换算法，ike 为自动，优先使用 IKEv2
    keyexchange = ike
    # 服务端公网 IP，可以是魔术字 %any，表示从本地 IP 地址表中取
    left = %any
    # 客户端 IP，同上
    right = %any
    # 指定服务端与客户端的 DNS，多个用“,”分隔
    leftdns = 8.8.8.8,8.8.4.4
    rightdns = 8.8.8.8,8.8.4.4
    # 服务端用于 ike 认证时使用的端口，默认为 500，如果使用了 nat 转发，则使用 4500
    # leftikeport = <port>
    # 服务器端虚拟 IP 地址
    # leftsourceip = %config
    # 客户端虚拟 IP 段
    rightsourceip = 10.0.0.0/24
    # 服务器端子网，魔术字 0.0.0.0/0 。如果为客户端分配虚拟 IP 地址的话，那表示之后要做 iptables 转发，那么服务器端就必须是用魔术字
    leftsubnet = 0.0.0.0/0
    # rightsubnet = <ip subnet>[[<proto/port>]][,...]
conn IKEv2-BASE
    # 服务器端根证书 DN 名称
    leftca = "C=CN, O=123si, CN=123si StrongSwan CA"
    # 服务器证书，可以是 PEM 或 DER 格式
    leftcert = server.cert.pem
    # 不指定客户端证书路径
    # rightcert = <path>
    # 指定服务器证书的公钥
    leftsigkey = server.pub.pem
    # rightsigkey = <raw public key> | <path to public key>
    # 是否发送服务器证书到客户端
    leftsendcert = always
    # 客户端不发送证书
    rightsendcert = never
    # 服务端认证方法，使用证书
    leftauth = pubkey
    # 客户端认证使用 EAP 扩展认证，貌似 eap-mschapv2 比较通用
    rightauth = eap-mschapv2
    # 服务端 ID，可以任意指定，默认为服务器证书的 subject，还可以是魔术字 %any，表示什么都行
    leftid = vpn.itnmg.net
    # 客户端 id，任意
    rightid = %any
# ios, mac os, win7+, linux
conn IKEv2-EAP
    also = IKEv2-BASE
    # 指定客户端 eap id
    eap_identity = %any
    # 不自动重置密钥
    rekey = no
    # 开启 IKE 消息分片
    fragmentation = yes
    # 当服务启动时，应该如何处理这个连接项。add 添加到连接表中。
    auto = add

我的配置：

# ipsec.conf - strongSwan IPsec configuration file
# basic configuration
config setup
    # strictcrlpolicy=yes
    uniqueids = never
# Add connections here.
# Sample VPN connections
#conn sample-self-signed
#      leftsubnet=10.1.0.0/16
#      leftcert=selfCert.der
#      leftsendcert=never
#      right=192.168.0.2
#      rightsubnet=10.2.0.0/16
#      rightcert=peerCert.der
#      auto=start
#conn sample-with-ca-cert
#      leftsubnet=10.1.0.0/16
#      leftcert=myCert.pem
#      right=192.168.0.2
#      rightsubnet=10.2.0.0/16
#      rightid="C=CH, O=Linux strongSwan CN=peer name"
#      auto=start
conn %default
    compress = yes
    esp = aes256-sha256,aes256-sha1,3des-sha1!
    ike = aes256-sha256-modp2048,aes256-sha1-modp2048,aes128-sha1-modp2048,3des-sha1-modp2048,aes256-sha256-modp1024,aes256-sha1-modp1024,aes128-sha1-modp1024,3des-sha1-modp1024!
    keyexchange = ike
    keyingtries = 1
    leftdns = 8.8.8.8,8.8.4.4
    rightdns = 8.8.8.8,8.8.4.4
conn IKEv2-BASE
    # 服务器端根证书 DN 名称
    leftca = "C=CN, O=123si, CN=123si StrongSwan CA"
    # 是否发送服务器证书到客户端
    leftsendcert = always
    # 客户端不发送证书
    rightsendcert = never
conn IKEv2-EAP
    leftca = "C=CN, O=123si, CN=123si StrongSwan CA"
    leftcert = server.cert.pem
    leftsendcert = always
    rightsendcert = never
    leftid = 48.85.166.86
    left = %any
    right = %any
    leftauth = pubkey
    rightauth = eap-mschapv2
    leftfirewall = yes
    leftsubnet = 0.0.0.0/0
    rightsourceip = 10.1.0.0/16
    fragmentation = yes
    rekey = no
    eap_identity = %any
    auto = add

2、修改 DNS 配置

strongSwan v5.1.2 之后，所有插件配置都分散在/etc/strongswan/strongswan.d/目录中。

编辑配置文件：

vim /etc/strongswan/strongswan.d/charon.conf

设置 Windows 公用 DNS，去掉dns1和dns2前面的井号（#）。

修改如下：

# Options for the charon IKE daemon.
charon {
    # Accept unencrypted ID and HASH payloads in IKEv1 Main Mode.
    # accept_unencrypted_mainmode_messages = no
    # Maximum number of half-open IKE_SAs for a single peer IP.
    # block_threshold = 5
    # Whether Certificate Revocation Lists (CRLs) fetched via HTTP or LDAP
    # should be saved under a unique file name derived from the public key of
    # the Certification Authority (CA) to /etc/ipsec.d/crls (stroke) or
    # /etc/swanctl/x509crl (vici), respectively.
    # cache_crls = no
    # Whether relations in validated certificate chains should be cached in
    # memory.
    # cert_cache = yes
    # Send Cisco Unity vendor ID payload (IKEv1 only).
    # cisco_unity = no
    # Close the IKE_SA if setup of the CHILD_SA along with IKE_AUTH failed.
    # close_ike_on_child_failure = no
    # Number of half-open IKE_SAs that activate the cookie mechanism.
    # cookie_threshold = 10
    # Delete CHILD_SAs right after they got successfully rekeyed (IKEv1 only).
    # delete_rekeyed = no
    # Delay in seconds until inbound IPsec SAs are deleted after rekeyings
    # (IKEv2 only).
    # delete_rekeyed_delay = 5
    # Use ANSI X9.42 DH exponent size or optimum size matched to cryptographic
    # strength.
    # dh_exponent_ansi_x9_42 = yes
    # Use RTLD_NOW with dlopen when loading plugins and IMV/IMCs to reveal
    # missing symbols immediately.
    # dlopen_use_rtld_now = no
    # DNS server assigned to peer via configuration payload (CP).
    # Windows 公用 DNS
    dns1 = 8.8.8.8
    # DNS server assigned to peer via configuration payload (CP).
    # Windows 公用 DNS
    dns2 = 8.8.4.4
    # Enable Denial of Service protection using cookies and aggressiveness
    # checks.
    # dos_protection = yes
    # Compliance with the errata for RFC 4753.
    # ecp_x_coordinate_only = yes
    # Free objects during authentication (might conflict with plugins).
    # flush_auth_cfg = no
    # Whether to follow IKEv2 redirects (RFC 5685).
    # follow_redirects = yes
    # Maximum size (complete IP datagram size in bytes) of a sent IKE fragment
    # when using proprietary IKEv1 or standardized IKEv2 fragmentation, defaults
    # to 1280 (use 0 for address family specific default values, which uses a
    # lower value for IPv4).  If specified this limit is used for both IPv4 and
    # IPv6.
    # fragment_size = 1280
    # Name of the group the daemon changes to after startup.
    # group =
    # Timeout in seconds for connecting IKE_SAs (also see IKE_SA_INIT DROPPING).
    # half_open_timeout = 30
    # Enable hash and URL support.
    # hash_and_url = no
    # Allow IKEv1 Aggressive Mode with pre-shared keys as responder.
    # i_dont_care_about_security_and_use_aggressive_mode_psk = no
    # Whether to ignore the traffic selectors from the kernel's acquire events
    # for IKEv2 connections (they are not used for IKEv1).
    # ignore_acquire_ts = no
    # A space-separated list of routing tables to be excluded from route
    # lookups.
    # ignore_routing_tables =
    # Maximum number of IKE_SAs that can be established at the same time before
    # new connection attempts are blocked.
    # ikesa_limit = 0
    # Number of exclusively locked segments in the hash table.
    # ikesa_table_segments = 1
    # Size of the IKE_SA hash table.
    # ikesa_table_size = 1
    # Whether to close IKE_SA if the only CHILD_SA closed due to inactivity.
    # inactivity_close_ike = no
    # Limit new connections based on the current number of half open IKE_SAs,
    # see IKE_SA_INIT DROPPING in strongswan.conf(5).
    # init_limit_half_open = 0
    # Limit new connections based on the number of queued jobs.
    # init_limit_job_load = 0
    # Causes charon daemon to ignore IKE initiation requests.
    # initiator_only = no
    # Install routes into a separate routing table for established IPsec
    # tunnels.
    # install_routes = yes
    # Install virtual IP addresses.
    # install_virtual_ip = yes
    # The name of the interface on which virtual IP addresses should be
    # installed.
    # install_virtual_ip_on =
    # Check daemon, libstrongswan and plugin integrity at startup.
    # integrity_test = no
    # A comma-separated list of network interfaces that should be ignored, if
    # interfaces_use is specified this option has no effect.
    # interfaces_ignore =
    # A comma-separated list of network interfaces that should be used by
    # charon. All other interfaces are ignored.
    # interfaces_use =
    # NAT keep alive interval.
    # keep_alive = 20s
    # Plugins to load in the IKE daemon charon.
    # load =
    # Determine plugins to load via each plugin's load option.
    # load_modular = no
    # Initiate IKEv2 reauthentication with a make-before-break scheme.
    # make_before_break = no
    # Maximum number of IKEv1 phase 2 exchanges per IKE_SA to keep state about
    # and track concurrently.
    # max_ikev1_exchanges = 3
    # Maximum packet size accepted by charon.
    # max_packet = 10000
    # Enable multiple authentication exchanges (RFC 4739).
    # multiple_authentication = yes
    # WINS servers assigned to peer via configuration payload (CP).
    # nbns1 =
    # WINS servers assigned to peer via configuration payload (CP).
    # nbns2 =
    # UDP port used locally. If set to 0 a random port will be allocated.
    # port = 500
    # UDP port used locally in case of NAT-T. If set to 0 a random port will be
    # allocated.  Has to be different from charon.port, otherwise a random port
    # will be allocated.
    # port_nat_t = 4500
    # Whether to prefer updating SAs to the path with the best route.
    # prefer_best_path = no
    # Prefer locally configured proposals for IKE/IPsec over supplied ones as
    # responder (disabling this can avoid keying retries due to
    # INVALID_KE_PAYLOAD notifies).
    # prefer_configured_proposals = yes
    # By default public IPv6 addresses are preferred over temporary ones (RFC
    # 4941), to make connections more stable. Enable this option to reverse
    # this.
    # prefer_temporary_addrs = no
    # Process RTM_NEWROUTE and RTM_DELROUTE events.
    # process_route = yes
    # Delay in ms for receiving packets, to simulate larger RTT.
    # receive_delay = 0
    # Delay request messages.
    # receive_delay_request = yes
    # Delay response messages.
    # receive_delay_response = yes
    # Specific IKEv2 message type to delay, 0 for any.
    # receive_delay_type = 0
    # Size of the AH/ESP replay window, in packets.
    # replay_window = 32
    # Base to use for calculating exponential back off, see IKEv2 RETRANSMISSION
    # in strongswan.conf(5).
    # retransmit_base = 1.8
    # Maximum jitter in percent to apply randomly to calculated retransmission
    # timeout (0 to disable).
    # retransmit_jitter = 0
    # Upper limit in seconds for calculated retransmission timeout (0 to
    # disable).
    # retransmit_limit = 0
    # Timeout in seconds before sending first retransmit.
    # retransmit_timeout = 4.0
    # Number of times to retransmit a packet before giving up.
    # retransmit_tries = 5
    # Interval in seconds to use when retrying to initiate an IKE_SA (e.g. if
    # DNS resolution failed), 0 to disable retries.
    # retry_initiate_interval = 0
    # Initiate CHILD_SA within existing IKE_SAs (always enabled for IKEv1).
    # reuse_ikesa = yes
    # Numerical routing table to install routes to.
    # routing_table =
    # Priority of the routing table.
    # routing_table_prio =
    # Whether to use RSA with PSS padding instead of PKCS#1 padding by default.
    # rsa_pss = no
    # Delay in ms for sending packets, to simulate larger RTT.
    # send_delay = 0
    # Delay request messages.
    # send_delay_request = yes
    # Delay response messages.
    # send_delay_response = yes
    # Specific IKEv2 message type to delay, 0 for any.
    # send_delay_type = 0
    # Send strongSwan vendor ID payload
    # send_vendor_id = no
    # Whether to enable Signature Authentication as per RFC 7427.
    # signature_authentication = yes
    # Whether to enable constraints against IKEv2 signature schemes.
    # signature_authentication_constraints = yes
    # The upper limit for SPIs requested from the kernel for IPsec SAs.
    # spi_max = 0xcfffffff
    # The lower limit for SPIs requested from the kernel for IPsec SAs.
    # spi_min = 0xc0000000
    # Number of worker threads in charon.
    # threads = 16
    # Name of the user the daemon changes to after startup.
    # user =
    crypto_test {
        # Benchmark crypto algorithms and order them by efficiency.
        # bench = no
        # Buffer size used for crypto benchmark.
        # bench_size = 1024
        # Time in ms during which crypto algorithm performance is measured.
        # bench_time = 50
        # Test crypto algorithms during registration (requires test vectors
        # provided by the test-vectors plugin).
        # on_add = no
        # Test crypto algorithms on each crypto primitive instantiation.
        # on_create = no
        # Strictly require at least one test vector to enable an algorithm.
        # required = no
        # Whether to test RNG with TRUE quality; requires a lot of entropy.
        # rng_true = no
    }
    host_resolver {
        # Maximum number of concurrent resolver threads (they are terminated if
        # unused).
        # max_threads = 3
        # Minimum number of resolver threads to keep around.
        # min_threads = 0
    }
    leak_detective {
        # Includes source file names and line numbers in leak detective output.
        # detailed = yes
        # Threshold in bytes for leaks to be reported (0 to report all).
        # usage_threshold = 10240
        # Threshold in number of allocations for leaks to be reported (0 to
        # report all).
        # usage_threshold_count = 0
    }
    processor {
        # Section to configure the number of reserved threads per priority class
        # see JOB PRIORITY MANAGEMENT in strongswan.conf(5).
        priority_threads {
        }
    }
    # Section containing a list of scripts (name = path) that are executed when
    # the daemon is started.
    start-scripts {
    }
    # Section containing a list of scripts (name = path) that are executed when
    # the daemon is terminated.
    stop-scripts {
    }
    tls {
        # List of TLS encryption ciphers.
        # cipher =
        # List of TLS key exchange methods.
        # key_exchange =
        # List of TLS MAC algorithms.
        # mac =
        # List of TLS cipher suites.
        # suites =
    }
    x509 {
        # Discard certificates with unsupported or unknown critical extensions.
        # enforce_critical = yes
    }
}

3、配置用户名与密码

编辑配置文件：

vim /etc/strongswan/ipsec.secrets

添加用户名和密码：

# ipsec.secrets - strongSwan IPsec secrets file
# 使用证书验证时的服务器端私钥
# 格式 : RSA <private key file> [ <passphrase> | %prompt ]
: RSA server.key.pem
# 使用预设加密密钥, 越长越好
# 格式 [ <id selectors> ] : PSK <secret>
%any %any : PSK "abcdef123456"
# EAP 方式, 格式同 psk 相同
UserName1 %any : EAP "UserPassword1"
UserName2 %any : EAP "UserPassword2"
# XAUTH 方式, 只适用于 IKEv1
# 格式 [ <servername> ] <username> : XAUTH "<password>"
UserName1 %any : XAUTH "UserPassword1"
UserName2 %any : XAUTH "UserPassword2"

4、开启内核转发

编辑系统配置文件：

vim /etc/sysctl.conf

在末尾处，添加如下配置项：

net.ipv4.ip_forward = 1
net.ipv6.conf.all.forwarding = 1

或者，执行下面命令添加到系统配置文件。

echo "net.ipv4.ip_forward = 1" >> /etc/sysctl.conf
echo "net.ipv6.conf.all.forwarding = 1" >> /etc/sysctl.conf

最后重新加载系统参数，使上面的配置生效，执行命令：

sysctl -p

五、配置防火墙

配置 CentOS 7 系统默认防火墙 FirewallD。

注意，以下命令没有指定--zone=public参数，都是针对默认区域public。

1、为区域添加服务

firewall-cmd --permanent --add-service="ipsec"

2、允许 AH 和 ESP 身份验证协议和加密协议通过防火墙

# ESP (the encrypted data packets)
firewall-cmd --permanent --add-rich-rule='rule protocol value="esp" accept'
# AH (authenticated headers)
firewall-cmd --permanent --add-rich-rule='rule protocol value="ah" accept'

3、开放 500 和 4500 端口

# IKE  (security associations)
firewall-cmd --permanent --add-port=500/udp
# IKE NAT Traversal (IPsec between natted devices)
firewall-cmd --permanent --add-port=4500/udp

4、启用 IP 伪装

firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="10.1.0.0/16" masquerade'

5、添加 nat 转发

firewall-cmd --permanen --add-rich-rule='rule family="ipv4" source address="10.1.0.0/16" forward-port port="4500" protocol="udp" to-port="4500"'
firewall-cmd --permanen --add-rich-rule='rule family="ipv4" source address="10.1.0.0/16" forward-port port="500" protocol="udp" to-port="500"'

6、重新加载防火墙配置

firewall-cmd --reload

7、显示所有公共区域（public）

firewall-cmd --list-all

查看上面命令执行结果。

六、strongSwan 服务操作

1、使用 strongswan 自身的命令

# 停止服务
strongswan stop
# 查看是否连接了客户端
strongswan status
# 查看命令帮助
strongswan --help

2、使用 systemctl 命令

# 设置开机启动 strongswan 服务
systemctl enable strongswan
# 启动服务
systemctl start strongswan
# 停止服务
systemctl stop strongswan
# 重启服务
systemctl restart strongswan
# 查看服务状态
systemctl status strongswan

注意，如果使用strongswan restart命令重启 strongSwan 后，再用systemctl status strongswan命令得不到正确的运行状态。

至此，服务端配置已完成。

七、客户端配置

IOS 系统

先导入 CA 证书，将之前创建的ca.cert.pem用 FTP 导出，写邮件以附件的方式发到邮箱, 在 IOS 浏览器登录邮箱，下载附件，安装 CA 证书。

1、使用 IKEv2 + EAP 认证

找到手机上“设置->VPN->添加配置”，选 IKEv2 。

• 描述：随便填
• 服务器：填 URL 或 IP
• 远程 ID：ipsec.conf 中的 leftid
• 用户鉴定：用户名
• 用户名：EAP 项用户名
• 密码：EAP 项密码

2、使用 IKEv2 + 客户端证书 认证

把之前的 .p12 证书（里面包含 CA 证书）发到邮箱在手机上打开。导入到手机（此时需要之前设置的证书密码）。

找到手机上“设置->VPN->添加配置’，选 IKEv2 。

• 描述：随便填
• 服务器：填 URL 或 IP
• 远程ID：ipsec.conf 中的 leftid
• 用户鉴定：证书
• 证书：选择安装完的客户端证书

3、使用 IKEv2 + 预设密钥 认证

找到手机上“设置->VPN->添加配置”，选 IKEv2 。

• 描述：随便填
• 服务器：填 URL 或 IP
• 远程ID：ipsec.conf 中的 leftid
• 用户鉴定：无
• 使用证书：关
• 密钥：PSK 项密钥

Windows 10

导入证书：

• 将 CA 根证书 ca.cert.pem 重命名为 ca.cert.crt；
• 双击 ca.cert.crt 开始安装证书；
• 点击安装证书；
• “存储位置”选择“本地计算机”，下一步；
• 选择“将所有的证书都放入下列存储区”，点浏览，选择“受信任的根证书颁发机构”，确定，下一步，完成；

建立连接：

• “控制面板”-“网络和共享中心”-“设置新的连接或网络”-“连接到工作区”-“使用我的 Internet 连接”；
• Internet 地址写服务器 IP 或 URL；
• 描述随便写；
• 用户名密码写之前配置的 EAP 的那个；
• 确定；
• 转到 控制面板网络和 Internet 网络连接；
• 在新建的 VPN 连接上右键属性然后切换到“安全”选项卡；
• VPN 类型选 IKEv2 ；
• 数据加密选“需要加密”；
• 身份认证这里需要说一下，如果想要使用 EAP 认证的话就选择“Microsoft : 安全密码(EAP-MSCHAP v2)”；想要使用私人证书认证的话就选择“使用计算机证书”；
• 再切换到“网络”选项卡，双击“Internet 协议版本 4”以打开属性窗口，这里说一下，如果你使用的是老版本的 Win10，可能会打不开属性窗口，这是已知的 Bug，升级最新版本即可解决；
• 点击“高级”按钮，勾选“在远程网络上使用默认网关”，确定退出；

Windows 7 导入证书略有不同

• 开始菜单搜索“cmd”，打开后输入 MMC（Microsoft 管理控制台）；
• “文件”-“添加/删除管理单元”，添加“证书”单元；
• 证书单元的弹出窗口中一定要选“计算机账户”，之后选“本地计算机”，确定；
• 在左边的“控制台根节点”下选择“证书”-“受信任的根证书颁发机构”-“证书”，右键“所有任务”-“导入”打开证书导入窗口；
• 选择 CA 证书 ca.cert.crt 导入即可；

注意，千万不要双击 .p12 证书导入！因为那样会导入到当前用户而不是本机计算机中。

八、可能遇到的问题

1. 关于 Windows 10 系统中 VPN 能正常连接，但不能打开网页的情况。

   这与“VPN 连接”属性中的“接口跃点数”设置有关。该设置用于设置网络接口的优先级，使用 cmd 执行命令route print查看路由表，知道其他接口的跃点数后，我们只要将“VPN 连接”的“接口跃点数”设置低于它们就可以了。设置好后，网络请求会优先使用“VPN 连接”。

   

   图为：接口跃点数的设置。

   

   图为：route print命令执行结果。

   图中“接口列表”第一列，用红色圈出的部分为跃点数，将“VPN 连接”的“接口跃点数”设置为 10 即可。

九、参考文献

• strongSwan - 官网
• IPSEC VPN on Centos 7 with StrongSwan
• CentOS 7 配置 IPSec-IKEv2 VPN, 适用于 ios, mac os, windows, linux.
• 在阿里云 CentOS 7上使用strongswan搭建IKEv2 VPN
• 一键搭建适用于Ubuntu/CentOS的IKEV2/L2TP的VPN

（完）