我不确定问题到底出在哪里。我很确定这是 OpenVPN 服务器上的一些 NAT 或 iptables 问题，但我缺乏解决该问题的网络知识。问题的关键在于我的 OpenVPN 服务器无法 ping 或连接到 Windows 客户端上的开放端口。但是，Windows 客户端可以连接到 OpenVPN 服务器。我意识到那里有一些非常相似的问题，但我无法通过他们的答案找出我的问题。
服务器配置：
port 1194
proto tcp
dev tun
ca ca.crt
key server.key
cert server.crt
dh dh2048.pem
server 10.8.0.0 255.255.255.0
ifconfig-pool-persist ipp.txt
push "redirect-gateway def1 bypass-dhcp"
push "dhcp-option DNS 192.168.0.150"
push "dhcp-option DNS 208.67.222.222"
push "dhcp-option DNS 208.67.220.220"
keepalive 10 120
comp-lzo
user nobody
group nobody
persist-key
persist-tun
status openvpn-status.log
verb 3
服务器 ifconfig：
[root@openvpn ~]# /sbin/ifconfig
eth0 Link encap:Ethernet HWaddr 08:00:27:09:ED:FC
inet addr:192.168.0.200 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: ::a00:27ff:fe09:edfc/64 Scope:Global
inet6 addr: fe80::a00:27ff:fe09:edfc/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:199562 errors:0 dropped:0 overruns:0 frame:0
TX packets:173845 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:105179115 (100.3 MiB) TX bytes:96774220 (92.2 MiB)
eth1 Link encap:Ethernet HWaddr 08:00:27:5E:CB:11
inet addr:10.0.3.15 Bcast:10.0.3.255 Mask:255.255.255.0
inet6 addr: fe80::a00:27ff:fe5e:cb11/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2 errors:0 dropped:0 overruns:0 frame:0
TX packets:12 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1180 (1.1 KiB) TX bytes:1416 (1.3 KiB)
eth2 Link encap:Ethernet HWaddr 08:00:27:9F:84:44
inet addr:192.168.56.200 Bcast:192.168.56.255 Mask:255.255.255.0
inet6 addr: fe80::a00:27ff:fe9f:8444/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:523 errors:0 dropped:0 overruns:0 frame:0
TX packets:51 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:53923 (52.6 KiB) TX bytes:3546 (3.4 KiB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:878 errors:0 dropped:0 overruns:0 frame:0
TX packets:878 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:135186 (132.0 KiB) TX bytes:135186 (132.0 KiB)
tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
inet addr:10.8.0.1 P-t-P:10.8.0.2 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:36245 errors:0 dropped:0 overruns:0 frame:0
TX packets:42614 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:4584112 (4.3 MiB) TX bytes:22527697 (21.4 MiB)
服务器 iptables：
*nat
:PREROUTING ACCEPT [1647:106875]
:POSTROUTING ACCEPT [66:4385]
:OUTPUT ACCEPT [66:4385]
-A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE
-A POSTROUTING -s 192.168.0.0/24 -o tun0 -j MASQUERADE
COMMIT
*filter
:INPUT ACCEPT [162:13810]
:FORWARD ACCEPT [986:57824]
:OUTPUT ACCEPT [27147:18531930]
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 1194 -j ACCEPT
-A FORWARD -s 192.168.0.0/24 -d 10.8.0.0/24 -i eth0 -o tun0 -m conntrack --ctstate NEW -j ACCEPT
-A FORWARD -s 10.8.0.0/24 -d 192.168.0.0/24 -i tun0 -o eth0 -m conntrack --ctstate NEW -j ACCEPT
-A FORWARD -s 10.8.0.0/24 -d 192.168.0.0/24 -i tun0 -o eth0 -m conntrack --ctstate NEW -j ACCEPT
-A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
COMMIT
服务器路由表：
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.8.0.2 * 255.255.255.255 UH 0 0 0 tun0
10.8.0.0 10.8.0.1 255.255.255.0 UG 0 0 0 tun0
10.0.3.0 * 255.255.255.0 U 0 0 0 eth1
192.168.0.0 * 255.255.255.0 U 0 0 0 eth0
192.168.56.0 * 255.255.255.0 U 0 0 0 eth2
link-local * 255.255.0.0 U 1002 0 0 eth0
link-local * 255.255.0.0 U 1003 0 0 eth1
link-local * 255.255.0.0 U 1004 0 0 eth2
default 192.168.0.1 0.0.0.0 UG 0 0 0 eth0
客户端配置：
client
dev tun
proto tcp
remote <MY_IP> <M_PORT>
resolv-retry infinite
remote-cert-tls server
nobind
persist-key
persist-tun
comp-lzo
verb 3
<ca>
-----BEGIN CERTIFICATE-----
....
-----END CERTIFICATE-----
</ca>
<cert>
-----BEGIN CERTIFICATE-----
....
-----END CERTIFICATE-----
</cert>
<key>
-----BEGIN PRIVATE KEY-----
....
-----END PRIVATE KEY-----
</key>