前言
以前连接回公司,经常都是使用 OpenVPN、PPTP、L2TP 什么的,感觉不是很难用,但也说不上很好用。但是因为大家都知道的原因,在 iOS 上 OpenVPN 基本上无法正常下载,这对于公司员工来说就比较麻烦了,因为并不是每个人都需要科学上网的。后来无意中发现了 OpenConnect VPN Server,感觉还不错,后来就用到公司网络上了。使用过一段时间,就考虑把家里的 OpenWrt 也装一个,这样外出的时候连回家里管理 NAS 也方便些,便有了此文。
前期准备
- 首先,你得有个刷了 OpenWrt 的路由器,版本Chaos Calmer 15.05
- 自己配置好 DDNS 等服务器。
- (可选)花钱或者免费弄一个服务器 SSL/TLS 证书
开工
安装 ocserv 和 ddns
我是命令行粉丝,所以大部分工作在 Terminal 下完成。
opkg update opkg install luci-app-ocserv opkg install luci-app-ddns
装好后的效果如下:安装 Web 界面的ocserv和ddns,其实装ddns并不是为了真正的动态域名,而是ocserv的脚本会检测系统中是否有ddns,如果有的话,ocserv的配置脚本会自动把动态域名设置为true,如果喜欢自己改脚本的,也可以不装ddns,这样可以解决点空间。
修改配置文件
安装好后,系统会自动生成以下 7 个文件:
/etc/ocserv/ca.pem /etc/ocserv/ca-key.pem /etc/ocserv/server-cert.pem /etc/ocserv/server-key.pem /etc/ocserv/ocserv.conf.template /etc/ocserv/pki/ca.tmpl /etc/ocserv/pki/server.tmpl
一般来说 CA 相关的可以不用管,如果你找了如 StartSSL 签了免费的证书的话,用他们签名过的公私钥替换server-cert.pem和server-key.pem就好了。其中ca.pem是服务器的 CA 证书,ca-key.pem是私钥,server-cert.pem是服务器证书,server-key.pem是服务器私钥。
接下来修改模板文件ocserv.conf.template,这个可以在命令行中用 Vim 操作,也可以在 Web 界面来操作,比如:
以下为使用「证书」方式来进行身份验证的,所以直接忽略系统默认的plain认证方式,如果使用该方式可以参考文章最后的参考文献。最终的配置文件如下:
# User authentication method. Could be set multiple times and in that case # all should succeed. # Options: certificate, pam. auth = "certificate" #auth = "pam" # The gid-min option is used by auto-select-group option, in order to # select the minimum group ID. #auth = "pam[gid-min=1000]" # The plain option requires specifying a password file which contains # entries of the following format. # "username:groupname:encoded-password" # One entry must be listed per line, and 'ocpasswd' can be used # to generate password entries. #auth = "|AUTH|" # A banner to be displayed on clients #banner = "Welcome to OpenWRT" #isolate-workers = true # When the server has a dynamic DNS address (that may change), # should set that to true to ask the client to resolve again on # reconnects. listen-host-is-dyndns = |DYNDNS| # Use listen-host to limit to specific IPs or to the IPs of a provided # hostname. #listen-host = [IP|HOSTNAME] # Limit the number of clients. Unset or set to zero for unlimited. #max-clients = 1024 max-clients = |MAX_CLIENTS| # Limit the number of client connections to one every X milliseconds # (X is the provided value). Set to zero for no limit. rate-limit-ms = 100 # Limit the number of identical clients (i.e., users connecting # multiple times). Unset or set to zero for unlimited. max-same-clients = |MAX_SAME| # TCP and UDP port number tcp-port = |PORT| |UDP|udp-port = |PORT| # Stats report time. The number of seconds after which each # worker process will report its usage statistics (number of # bytes transferred etc). This is useful when accounting like # radius is in use. #stats-report-time = 360 # Keepalive in seconds keepalive = 32400 # Dead peer detection in seconds. dpd = |DPD| # Dead peer detection for mobile clients. The needs to # be much higher to prevent such clients being awaken too # often by the DPD messages, and save battery. # (clients that send the X-AnyConnect-Identifier-DeviceType) #mobile-dpd = 1800 # MTU discovery (DPD must be enabled) try-mtu-discovery = false # The key and the certificates of the server # The key may be a file, or any URL supported by GnuTLS (e.g., # tpmkey:uuid=xxxxxxx-xxxx-xxxx-xxxx-xxxxxxxx;storage=user # or pkcs11:object=my-vpn-key;object-type=private) # # There may be multiple certificate and key pairs and each key # should correspond to the preceding certificate. server-cert = /etc/ocserv/server-cert.pem server-key = /etc/ocserv/server-key.pem # Diffie-Hellman parameters. Only needed if you require support # for the DHE ciphersuites (by default this server supports ECDHE). # Can be generated using: # certtool --generate-dh-params --outfile /path/to/dh.pem #dh-params = /path/to/dh.pem # If you have a certificate from a CA that provides an OCSP # service you may provide a fresh OCSP status response within # the TLS handshake. That will prevent the client from connecting # independently on the OCSP server. # You can update this response periodically using: # ocsptool --ask --load-cert=your_cert --load-issuer=your_ca --outfile response # Make sure that you replace the following file in an atomic way. #ocsp-response = /path/to/ocsp.der # In case PKCS #11 or TPM keys are used the PINs should be available # in files. The srk-pin-file is applicable to TPM keys only, and is the # storage root key. #pin-file = /path/to/pin.txt #srk-pin-file = /path/to/srkpin.txt # The Certificate Authority that will be used to verify # client certificates (public keys) if certificate authentication # is set. ca-cert = /etc/ocserv/ca.pem # The object identifier that will be used to read the user ID in the client # certificate. The object identifier should be part of the certificate's DN # Useful OIDs are: # CN = 2.5.4.3, UID = 0.9.2342.19200300.100.1.1 cert-user-oid = 2.5.4.3 # The object identifier that will be used to read the user group in the # client certificate. The object identifier should be part of the certificate's # DN. Useful OIDs are: # OU (organizational unit) = 2.5.4.11 #cert-group-oid = 2.5.4.11 # The revocation list of the certificates issued by the 'ca-cert' above. #crl = /etc/ocserv/crl.pem # Uncomment this to enable compression negotiation (LZS, LZ4). |COMPRESSION|compression = true # GnuTLS priority string tls-priorities = "NORMAL:%SERVER_PRECEDENCE:%COMPAT:-VERS-SSL3.0" # To enforce perfect forward secrecy (PFS) on the main channel. #tls-priorities = "NORMAL:%SERVER_PRECEDENCE:%COMPAT:-VERS-SSL3.0:-RSA" # The time (in seconds) that a client is allowed to stay connected prior # to authentication auth-timeout = 40 # The time (in seconds) that a client is allowed to stay idle (no traffic) # before being disconnected. Unset to disable. #idle-timeout = 1200 # The time (in seconds) that a mobile client is allowed to stay idle (no # traffic) before being disconnected. Unset to disable. #mobile-idle-timeout = 2400 # The time (in seconds) that a client is not allowed to reconnect after # a failed authentication attempt. min-reauth-time = 360 # Banning clients in ocserv works with a point system. IP addresses # that get a score over that configured number are banned for # min-reauth-time seconds. By default a wrong password attempt is 10 points, # a KKDCP POST is 1 point, and a connection is 1 point. Note that # due to difference processes being involved the count of points # will not be real-time precise. # # Score banning cannot be reliably used when receiving proxied connections # locally from an HTTP server (i.e., when listen-clear-file is used). # # Set to zero to disable. max-ban-score = 50 # The time (in seconds) that all score kept for a client is reset. ban-reset-time = 300 # In case you'd like to change the default points. #ban-points-wrong-password = 10 #ban-points-connection = 1 #ban-points-kkdcp = 1 # Cookie timeout (in seconds) # which he can reconnect. That cookie will be invalided if not # used within this timeout value. On a user disconnection, that # cookie will also be active for this time amount prior to be # invalid. That should allow a reasonable amount of time for roaming # between different networks. cookie-timeout = 300 # Whether roaming is allowed, i.e., if true a cookie is # restricted to a single IP address and cannot be re-used # from a different IP. deny-roaming = false # ReKey time (in seconds) # ocserv will ask the client to refresh keys periodically once # this amount of seconds is elapsed. Set to zero to disable. rekey-time = 172800 # ReKey method # Valid options: ssl, new-tunnel # ssl: Will perform an efficient rehandshake on the channel allowing # a seamless connection during rekey. # new-tunnel: Will instruct the client to discard and re-establish the channel. # Use this option only if the connecting clients have issues with the ssl # option. rekey-method = ssl # Script to call when a client connects and obtains an IP # Parameters are passed on the environment. # REASON, USERNAME, GROUPNAME, HOSTNAME (the hostname selected by client), # DEVICE, IP_REAL (the real IP of the client), IP_LOCAL (the local IP # in the P-t-P connection), IP_REMOTE (the VPN IP of the client), # ID (a unique numeric ID); REASON may be "connect" or "disconnect". # These scripts are not needed if you have setup an interface for all vpns+ # devices. #connect-script = /usr/bin/ocserv-script #disconnect-script = /usr/bin/ocserv-script # UTMP use-utmp = false # Whether to enable support for the occtl tool (i.e., either through D-BUS, # or via a unix socket). use-occtl = true # socket file used for IPC with occtl. You only need to set that, # if you use more than a single servers. occtl-socket-file = /var/run/occtl.socket # PID file. It can be overriden in the command line. pid-file = /var/run/ocserv.pid # The default server directory. Does not require any devices present. chroot-dir = /var/lib/ocserv # socket file used for IPC, will be appended with .PID # It must be accessible within the chroot environment (if any) #socket-file = /var/run/ocserv-socket socket-file = ocserv-socket # The user the worker processes will be run as. It should be # unique (no other services run as this user). run-as-user = ocserv run-as-group = ocserv # Set the protocol-defined priority (SO_PRIORITY) for packets to # be sent. That is a number from 0 to 6 with 0 being the lowest # priority. Alternatively this can be used to set the IP Type- # Of-Service, by setting it to a hexadecimal number (e.g., 0x20). # This can be set per user/group or globally. #net-priority = 3 # Set the VPN worker process into a specific cgroup. This is Linux # specific and can be set per user/group or globally. #cgroup = "cpuset,cpu:test" # # Network settings # # The name of the tun device device = vpns # Whether the generated IPs will be predictable, i.e., IP stays the # same for the same user when possible. predictable-ips = |PREDICTABLE_IPS| # The default domain to be advertised |ENABLE_DEFAULT_DOMAIN|default-domain = |DEFAULT_DOMAIN| # The pool of addresses that leases will be given from. ipv4-network = |IPV4ADDR| ipv4-netmask = |NETMASK| # The advertized DNS server. Use multiple lines for # multiple servers. # dns = fc00::4be0 #dns = 192.168.1.2 # The NBNS server (if any) #nbns = 192.168.1.3 # The IPv6 subnet that leases will be given from. |ENABLE_IPV6|ipv6-network = |IPV6ADDR| |ENABLE_IPV6|ipv6-prefix = |IPV6PREFIX| # The domains over which the provided DNS should be used. Use # multiple lines for multiple domains. #split-dns = example.com # Prior to leasing any IP from the pool ping it to verify that # it is not in use by another (unrelated to this server) host. ping-leases = false # Unset to assign the default MTU of the device # mtu = # Unset to enable bandwidth restrictions (in bytes/sec). The # setting here is global, but can also be set per user or per group. #rx-data-per-sec = 40000 #tx-data-per-sec = 40000 # The number of packets (of MTU size) that are available in # the output buffer. The default is low to improve latency. # Setting it higher will improve throughput. #output-buffer = 10 # Routes to be forwarded to the client. If you need the # client to forward routes to the server, you may use the # config-per-user/group or even connect and disconnect scripts. # # To set the server as the default gateway for the client just # comment out all routes from the server. #route = 192.168.1.0/255.255.255.0 #route = 192.168.5.0/255.255.255.0 #route = fef4:db8:1000:1001::/64 # Configuration files that will be applied per user connection or # per group. Each file name on these directories must match the username # or the groupname. # The options allowed in the configuration files are dns, nbns, # ipv?-network, ipv4-netmask, ipv6-prefix, rx/tx-per-sec, iroute, route, # net-priority and cgroup. # # Note that the 'iroute' option allows to add routes on the server # based on a user or group. The syntax depends on the input accepted # by the commands route-add-cmd and route-del-cmd (see below). config-per-user = /etc/ocserv/config-per-user/ config-per-group = /etc/ocserv/config-per-group/ # When config-per-xxx is specified and there is no group or user that # matches, then utilize the following configuration. #default-user-config = /etc/ocserv/defaults/user.conf #default-group-config = /etc/ocserv/defaults/group.conf # Groups that a client is allowed to select from. # A client may belong in multiple groups, and in certain use-cases # it is needed to switch between them. For these cases the client can # select prior to authentication. Add multiple entries for multiple groups. #select-group = group1 #select-group = group2[My group 2] #select-group = tost[The tost group] # The name of the group that if selected it would allow to use # the assigned by default group. #default-select-group = DEFAULT # Instead of specifying manually all the allowed groups, you may instruct # ocserv to scan all available groups and include the full list. That # option is only functional on plain authentication. #auto-select-group = true # The system command to use to setup a route. %{R} will be replaced with the # route/mask and %{D} with the (tun) device. # # The following example is from linux systems. %{R} should be something # like 192.168.2.0/24 route-add-cmd = "/sbin/route add -net %{R} dev %{D}" route-del-cmd = "/sbin/route del -net %{R} dev %{D}" # This option allows to forward a proxy. The special strings '%{U}' # and '%{G}', if present will be replaced by the username and group name. #proxy-url = http://example.com/ #proxy-url = http://example.com/%{U}/%{G}/hello # # The following options are for (experimental) AnyConnect client # compatibility. # Client profile xml. A sample file exists in doc/profile.xml. # This file must be accessible from inside the worker's chroot. # It is not used by the openconnect client. #user-profile = profile.xml # Binary files that may be downloaded by the CISCO client. Must # be within any chroot environment. #binary-files = /path/to/binaries # Unless set to false it is required for clients to present their # certificate even if they are authenticating via a previously granted # cookie and complete their authentication in the same TCP connection. # Legacy CISCO clients do not do that, and thus this option should be # set for them. cisco-client-compat = |CISCO_COMPAT| #Advanced options # Option to allow sending arbitrary custom headers to the client after # authentication and prior to VPN tunnel establishment. #custom-header = "X-My-Header: hi there"
主要的改动点:
- 认证方式修改为 certificate
- 禁用 banner
- 打开 ca-cert
- 将 cert-user-oid 修改为 CN (2.5.4.3) 识别
当ocserv服务启动的时候,会自动生成/var/etc/ocserv.conf文件作为最终的配置文件。
设置路由表、转发规则和端口映射
修改完配置文件以后,我们还需要设置路由表。因为我不需要 OpenWrt 代理所有流量,仅仅需要可以访问到内网,所以我只做了一个路由表,就是我的内网网段,如下图:
接下来添加自定义防火墙,或修改 firewall 文件/etc/firewall.user,增加如下内容:
iptables -A input_rule -i vpns+ -j ACCEPT iptables -A forwarding_rule -i vpns+ -j ACCEPT iptables -A forwarding_rule -o vpns+ -j ACCEPT iptables -A output_rule -o vpns+ -j ACCEPT
添加防火墙规则后重启服务。
最后 在防火墙-添加通信规则,ocserv安装后默认使用4443端口,如图:
启动 ocserv 服务
/etc/init.d/ocserv enable /etc/init.d/ocserv start
这个命令很简单,另外,也可以在 luci 中选择Enable server来打开ocserv服务。然而,在你重启后,ocserv服务从来就没有自动启动过!!!所以,我们还得做些 tweaking。
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在/etc/rc.local文件的exit前面增加两行:
/etc/init.d/ocserv restart sleep 5
同时创建一个/root/ocservup.sh脚本,防止ocserv进程意外被杀:
#!/bin/sh killall -0 ocserv 2> /dev/null if [ $? != 0 ] then logger \"$0: Starting ocserv ...\" /usr/sbin/ocserv -c /var/etc/ocserv.conf else logger \"$0: ocserv already running: $(pidof ocserv)\" fi
记得执行chmod +x /root/ocservup.sh给该脚本添加可执行属性。然后把该脚本添加到crontab中:
3 */2 * * * /root/ocservup.sh
至此,整个配置完成,可以重启试试。
参考文献