更新时间：2024-10-11 GMT+08:00
示例：使用OpenSwan配置云上云下互通
操作场景
云端在VPC中购买了VPN网关和连接，云下客户使用主机安装IPsec软件与云端对接，客户主机在出口网络进行了一对一的NAT映射。
拓扑连接
本场景拓扑连接及策略协商配置信息如图 拓扑连接及策略协商配置信息所示。
云上VPC的VPN网关IP：11.11.11.11，本地子网：192.168.200.0/24。
客户主机NAT映射IP：22.22.22.22，本地子网：192.168.222.0/24。
云端ECS与客户主机的本地IP地址分别为192.168.200.200和192.168.222.222。
VPN连接的协商参数使用华为云缺省配置。
配置步骤
本实例以在CentOs6.8中配置Openswan IPsec客户端为例进行介绍。
- 安装Openswan客户端。
yum install -y openswan
- 开启IPv4转发。
vim /etc/sysctl.conf
- 在配置文件中增加如下内容：
net.ipv4.ip_forward = 1
- 执行/sbin/sysctl -p命令，使转发配置参数生效。
- 在配置文件中增加如下内容：
- iptables配置。
确认关闭firewall或允许数据流转发，查询命令：iptables -L
iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination - 预共享密钥配置。
vim /etc/ipsec.d/open_IPsec.secrets
在配置文件中增加如下内容：22.22.22.22 11.11.11.11 : psk "IPsec-key"
格式：本地用于连接的IP+空格+远端网关IP+空格+英文冒号+空格+PSK+预共享密钥，冒号的两边都有空格，PSK大小写均可，密钥用英文双引号。
- IPsec连接配置。
vim /etc/ipsec.d/open_IPsec.conf
在配置文件中增加如下内容：conn openswan_IPsec # 定义连接名称为openswan_IPsec type=tunnel # 开启隧道模式 auto=start # 可选择add、route和start left=192.168.222.222 # 本地IP，nat场景选择真实的主机地址 leftid=22.22.22.22 # 本地标识ID leftsourceip=22.22.22.22 # 如果存在nat，源地址选择nat后的IP leftsubnet=192.168.222.0/24 # 本地子网 leftnexthop=22.22.22.1 # nat场景下一跳选择nat后的网关IP right=11.11.11.11 # 远端VPN网关IP rightid=11.11.11.11 # 远端标识ID rightsourceip=11.11.11.11 # 远端源地址选择VPN网关IP rightsubnet=192.168.200.0/24 # 远端子网 rightnexthop=%defaultroute # 远端路由按缺省配置 authby=secret # 定义认证方式为PSK keyexchange=ike # ike密钥交换方式 ike=aes128-sha1;modp1536 # 按照对端配置定义ike阶段算法和group ikev2=never # 关闭IKEv2版本 ikelifetime=86400s # ike阶段生命周期 phase2=esp # 二阶段传输格式 phase2alg=aes128-sha1;modp1536 # 按照对端配置定义IPsec阶段算法和group，modp1536=DH group 5 pfs=yes # 开启PFS compress=no # 关闭压缩 salifetime=3600s # 二阶段生命周期
配置完成后通过命令ipsec verify进行配置项校验。如果回显信息全部为OK时，表示配置成功。ipsec verify Verifying installed system and configuration files Version check and IPsec on-path [OK] Libreswan 3.25 (netkey) on 3.10.0-957.5.1.el7.x86_64 Checking for IPsec support in kernel [OK] NETKEY: Testing XFRM related proc values ICMP default/send_redirects [OK] ICMP default/accept_redirects [OK] XFRM larval drop [OK] Pluto IPsec.conf syntax [OK] Two or more interfaces found, checking IP forwarding[OK] Checking rp_filter [OK] Checking that pluto is running [OK] Pluto listening for IKE on udp 500 [OK] Pluto listening for IKE/NAT-T on udp 4500 [OK] Pluto IPsec.secret syntax [OK] Checking 'ip' command [OK] Checking 'iptables' command [OK] Checking 'prelink' command does not interfere with FIPS[OK] Checking for obsolete IPsec.conf options [OK]若回显信息出现如下报错：Checking rp_filter [ENABLED] /proc/sys/net/ipv4/conf/default/rp_filter [ENABLED] /proc/sys/net/ipv4/conf/lo/rp_filter [ENABLED] /proc/sys/net/ipv4/conf/eth0/rp_filter [ENABLED] /proc/sys/net/ipv4/conf/eth1/rp_filter [ENABLED] /proc/sys/net/ipv4/conf/ip_vti01/rp_filter [ENABLED]
通过如下命令解决：echo 0 > /proc/sys/net/ipv4/conf/all/rp_filter echo 0 > /proc/sys/net/ipv4/conf/default/rp_filter echo 0 > /proc/sys/net/ipv4/conf/eth0/rp_filter echo 0 > /proc/sys/net/ipv4/conf/eth1/rp_filter echo 0 > /proc/sys/net/ipv4/conf/lo/rp_filter echo 0 > /proc/sys/net/ipv4/conf/ip_vti01/rp_filter
- 启动服务。
service ipsec stop # 关闭服务
service ipsec start # 启动服务
service ipsec restart # 重启服务
ipsec auto --down openswan_IPsec # 关闭连接
ipsec auto --up openswan_IPsec # 开启连接
每次修改配置都需要重启服务，并重新开启连接。
配置验证
通过查询IPsec的状态，结果显示如下信息（摘录），查询状态命令：ipsec --status。
Connection list: 000 000 "openswan_IPsec": 192.168.222.0/24===192.168.222.222<192.168.222.222>[22.22.22.22]---22.22.22.1...11.11.11.11<11.11.11.11>===192.168.200.0/24; erouted; eroute owner: #30 000 "openswan_IPsec": oriented; my_ip=22.22.22.22; their_ip=11.11.11.11; my_updown=IPsec _updown; 000 "openswan_IPsec": xauth us:none, xauth them:none, my_username=[any]; their_username=[any] 000 "openswan_IPsec": our auth:secret, their auth:secret 000 "openswan_IPsec": modecfg info: us:none, them:none, modecfg policy:push, dns:unset, domains:unset, banner:unset, cat:unset; 000 "openswan_IPsec": labeled_IPsec:no; 000 "openswan_IPsec": policy_label:unset; 000 "openswan_IPsec": ike_life: 86400s; IPsec_life: 3600s; replay_window: 32; rekey_margin: 540s; rekey_fuzz: 100%; keyingtries: 0; 000 "openswan_IPsec": retransmit-interval: 500ms; retransmit-timeout: 60s; 000 "openswan_IPsec": initial-contact:no; cisco-unity:no; fake-strongswan:no; send-vendorid:no; send-no-esp-tfc:no; 000 "openswan_IPsec": policy: PSK+ENCRYPT+TUNNEL+PFS+UP+IKEV1_ALLOW+SAREF_TRACK+IKE_FRAG_ALLOW+ESN_NO; 000 "openswan_IPsec": conn_prio: 24,24; interface: eth0; metric: 0; mtu: unset; sa_prio:auto; sa_tfc:none; 000 "openswan_IPsec": nflog-group: unset; mark: unset; vti-iface:unset; vti-routing:no; vti-shared:no; nic-offload:auto; 000 "openswan_IPsec": our idtype: ID_IPV4_ADDR; our id=1.1.1.1; their idtype: ID_IPV4_ADDR; their id=2.2.2.2 000 "openswan_IPsec": dpd: action:hold; delay:0; timeout:0; nat-t: encaps:auto; nat_keepalive:yes; ikev1_natt:both 000 "openswan_IPsec": newest ISAKMP SA: #3; newest IPsec SA: #30; 000 "openswan_IPsec": IKE algorithms: AES_CBC_128-HMAC_SHA1-MODP1536 000 "openswan_IPsec": IKE algorithm newest: AES_CBC_128-HMAC_SHA1-MODP1536 000 "openswan_IPsec": ESP algorithms: AES_CBC_128-HMAC_SHA1_96-MODP1536 000 "openswan_IPsec": ESP algorithm newest: AES_CBC_128-HMAC_SHA1_96; pfsgroup=MODP1536 000 000 Total IPsec connections: loaded 1, active 1 000 000 State Information: DDoS cookies not required, Accepting new IKE connections 000 IKE SAs: total(1), half-open(0), open(0), authenticated(1), anonymous(0) 000 IPsec SAs: total(1), authenticated(1), anonymous(0) 000 000 #3: "openswan_IPsec":4500 STATE_MAIN_R3 (sent MR3, ISAKMP SA established); EVENT_SA_REPLACE in 15087s; newest ISAKMP; lastdpd=-1s(seq in:0 out:0); idle; import:admin initiate 000 #30: "openswan_IPsec":4500 STATE_QUICK_I2 (sent QI2, IPsec SA established); EVENT_SA_REPLACE in 1744s; newest IPsec; eroute owner; isakmp#3; idle; import:admin initiate 000 #30: "openswan_IPsec" esp.b810a24@11.11.11.11 esp.aab7b496@192.168.222.222 tun.0@11.11.11.11 tun.0@192.168.222.222 ref=0 refhim=0 Traffic: ESPin=106KB ESPout=106KB! ESPmax =4194303B
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