我使用的是 OpenBSD 5.7-amd64，并应用了最新的补丁。
我使用以下命令下载并安装了适用于 OpenBSD 5.7 的 OpenVPN（软件包版本：openvpn-2.3.6.tgz）：
sudo pkg_add -vi openvpn
我更改为 .ovpn 文件所在的目录：
cd openvpn-configs
我选择一个 ovpn 文件（例如 uk.ovpn）并输入以下命令：
sudo openvpn uk.ovpn
我的终端上闪现出一行行文字，最后出现以下消息：
Initialization Sequence Completed
表明我已连接到英国服务器。
我启动 Firefox 并输入 URL。
浏览器中什么也没有出现。
我打开另一个终端并输入：
ping microsoft.com
没有记录 ping。
怎么了？
为了响应 mjturner 提供更多信息的请求，以下是更多详细信息。
请注意，在安装操作系统期间，OpenBSD 提供的基本 pf 防火墙默认启用。而且在安装操作系统的过程中，当被问及是否配置/开启IPv6时，我回答“否”。
VPN连接日志详情：
Tue Jul 14 00:00:17 2015 OpenVPN 2.3.6 x86_64-unknown-openbsd5.7 [SSL (OpenSSL)] [LZO] [MH] [IPv6] built on Mar 7 2015
Tue Jul 14 00:00:17 2015 library versions: LibreSSL 2.1, LZO 2.08
Tue Jul 14 00:00:17 2015 WARNING: file 'auth.txt' is group or others accessible
Tue Jul 14 00:00:17 2015 Socket Buffers: R=[41600->65536] S=[9216->65536]
Tue Jul 14 00:00:17 2015 UDPv4 link local: [undef]
Tue Jul 14 00:00:17 2015 UDPv4 link remote: [AF_INET]111.222.333.444:443
Tue Jul 14 00:00:19 2015 TLS: Initial packet from [AF_INET]111.222.333.444:443, sid=16-alphanumeric-string
Tue Jul 14 00:00:19 2015 WARNING: this configuration may cache passwords in memory -- use the auth-nocache option to prevent this
Tue Jul 14 00:00:20 2015 VERIFY OK: depth=1, [particulars of commercial VPN service provider]
Tue Jul 14 00:00:20 2015 Validating certificate key usage
Tue Jul 14 00:00:20 2015 ++ Certificate has key usage 00a0, expects 00a0
Tue Jul 14 00:00:20 2015 VERIFY KU OK
Tue Jul 14 00:00:20 2015 Validating certificate extended key usage
Tue Jul 14 00:00:20 2015 ++ Certificate has EKU (str) TLS Web Server Authentication, expects TLS Web Server Authentication
Tue Jul 14 00:00:20 2015 VERIFY EKU OK
Tue Jul 14 00:00:20 2015 VERIFY OK: depth=0, [particulars of commercial VPN service provider]
Tue Jul 14 00:00:21 2015 Data Channel Encrypt: Cipher 'BF-CBC' initialized with 128 bit key
Tue Jul 14 00:00:21 2015 Data Channel Encrypt: Using 160 bit message hash 'SHA1' for HMAC authentication
Tue Jul 14 00:00:21 2015 Data Channel Decrypt: Cipher 'BF-CBC' initialized with 128 bit key
Tue Jul 14 00:00:21 2015 Data Channel Decrypt: Using 160 bit message hash 'SHA1' for HMAC authentication
Tue Jul 14 00:00:21 2015 Control Channel: TLSv1, cipher TLSv1/SSLv3 DHE-RSA-AES256-SHA, 2048 bit RSA
Tue Jul 14 00:00:21 2015 [VPN-UK] Peer Connection Initiated with [AF_INET]111.222.333.444:443
Tue Jul 14 00:00:23 2015 SENT CONTROL [VPN-UK]: 'PUSH_REQUEST' (status=1)
Tue Jul 14 00:00:24 2015 PUSH: Received control message: 'PUSH_REPLY,redirect-gateway def1,dhcp-option DNS 208.67.222.222,dhcp-option DNS 208.67.220.220,route 10.9.0.1,topology net30,ping 5,ping-restart 30,ifconfig 10.9.0.6 10.9.0.5'
Tue Jul 14 00:00:24 2015 OPTIONS IMPORT: timers and/or timeouts modified
Tue Jul 14 00:00:24 2015 OPTIONS IMPORT: --ifconfig/up options modified
Tue Jul 14 00:00:24 2015 OPTIONS IMPORT: route options modified
Tue Jul 14 00:00:24 2015 OPTIONS IMPORT: --ip-win32 and/or --dhcp-option options modified
Tue Jul 14 00:00:24 2015 ROUTE_GATEWAY 192.168.220.1
Tue Jul 14 00:00:24 2015 TUN/TAP device /dev/tun0 opened
Tue Jul 14 00:00:24 2015 do_ifconfig, tt->ipv6=0, tt->did_ifconfig_ipv6_setup=0
Tue Jul 14 00:00:24 2015 /sbin/ifconfig tun0 10.9.0.6 10.9.0.5 mtu 1500 netmask 255.255.255.255 up -link0
Tue Jul 14 00:00:26 2015 /sbin/route add -net 111.222.333.444 192.168.220.1 -netmask 255.255.255.255
add net 111.222.333.444: gateway 192.168.220.1
Tue Jul 14 00:00:26 2015 /sbin/route add -net 0.0.0.0 10.9.0.5 -netmask 128.0.0.0
add net 0.0.0.0: gateway 10.9.0.5
Tue Jul 14 00:00:26 2015 /sbin/route add -net 128.0.0.0 10.9.0.5 -netmask 128.0.0.0
add net 128.0.0.0: gateway 10.9.0.5
Tue Jul 14 00:00:26 2015 /sbin/route add -net 10.9.0.1 10.9.0.5 -netmask 255.255.255.255
add net 10.9.0.1: gateway 10.9.0.5
Tue Jul 14 00:00:26 2015 Initialization Sequence Completed
ifconfig -aVPN 连接开启时的详细信息：
$ ifconfig -a
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 32768
priority: 0
groups: lo
inet6 xx11::1%lo0 prefixlen 64 scopeid 0x3
inet6 ::1 prefixlen 128
inet 127.0.0.1 netmask 0xff000000
re0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
lladdr [MAC address of network card]
priority: 0
groups: egress
media: Ethernet autoselect (100baseTX full-duplex,rxpause,txpause)
status: active
inet 192.168.220.176 netmask 0xffffff00 broadcast 192.168.220.255
enc0: flags=0<>
priority: 0
groups: enc
status: active
pflog0: flags=141<UP,RUNNING,PROMISC> mtu 33144
priority: 0
groups: pflog
tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500
priority: 0
groups: tun
status: active
inet 10.9.0.6 --> 10.9.0.5 netmask 0xffffffff
netstat -nr -f inetVPN 连接开启时的详细信息：
$ netstat -nr -f inet
Routing tables
Internet:
Destination Gateway Flags Refs Use Mtu Prio Iface
0/1 10.9.0.5 UGS 0 0 - 8 tun0
default 192.168.220.1 UGS 1 137 - 8 re0
10.9.0.1/32 10.9.0.5 UGS 0 0 - 8 tun0
10.9.0.5 10.9.0.6 UH 3 0 - 4 tun0
10.9.0.6 10.9.0.6 UHl 0 0 - 1 lo0
111.222.333.444/32 192.168.220.1 UGS 0 0 - 8 re0
127/8 127.0.0.1 UGRS 0 0 32768 8 lo0
127.0.0.1 127.0.0.1 UHl 1 4 32768 1 lo0
128/1 10.9.0.5 UGS 0 0 - 8 tun0
192.168.220/24 link#1 UC 1 0 - 4 re0
192.168.220.1 [MAC-router] UHLc 2 0 - 4 re0
192.168.220.176 [MAC-network card] UHLl 0 0 - 1 lo0
192.168.220.255 link#1 UHLb 0 0 - 1 re0
224/4 link#1 UCS 0 0 - 8 re0
digVPN 连接开启时的详细信息：
$ dig +short microsoft.com
;; connection timed out; no servers could be reached
$