linux kvm 虛擬機 nat 網絡 iptables 宿主機端口轉發到虛擬機

我安裝了kvm，並使用vmbuilder在服務器上設置了多個guest虛擬機。這是以下配置：

server host1 (xxx.xxx.xxx.xxx) ->  guest vm1 (192.168.122.203)
                               ->  guest vm2 (192.168.122.204)

其中xxx.xxx.xxx.xxx是host1的固定IP地址。

我想使用以下命令連接到vm1：

ssh username@host1 -p 2222

我試圖通過在iptables中添加以下規則來做到這一點：

sudo iptables --table nat --append PREROUTING --protocol tcp --destination xxx.xxx.xxx.xxx --destination-port 2222 --jump DNAT --to-destination 192.168.122.203:22

但是我跑步時出現超時：

ssh username@host1 -p 2222

這是我的iptables規則：

sudo iptables -nL -v --line-numbers -t nat
Chain PREROUTING (policy ACCEPT 32446 packets, 3695K bytes)
num   pkts bytes target     prot opt in     out     source               destination         
1        7   420 DNAT       tcp  --  *      *       0.0.0.0/0            xxx.xxx.xxx.xxx        tcp dpt:2222 to:192.168.122.203:22

Chain INPUT (policy ACCEPT 8961 packets, 968K bytes)
num   pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 350 packets, 23485 bytes)
num   pkts bytes target     prot opt in     out     source               destination         

Chain POSTROUTING (policy ACCEPT 357 packets, 23905 bytes)
num   pkts bytes target     prot opt in     out     source               destination         
1      151  9060 MASQUERADE  tcp  --  *      *       192.168.122.0/24    !192.168.122.0/24     masq ports: 1024-65535
2       99  7524 MASQUERADE  udp  --  *      *       192.168.122.0/24    !192.168.122.0/24     masq ports: 1024-65535
3        3   252 MASQUERADE  all  --  *      *       192.168.122.0/24    !192.168.122.0/24



sudo iptables -nL -v --line-numbers 
Chain INPUT (policy ACCEPT 14 packets, 1147 bytes)
num   pkts bytes target     prot opt in     out     source               destination         
1      454 30229 ACCEPT     udp  --  virbr0 *       0.0.0.0/0            0.0.0.0/0            udp dpt:53
2        0     0 ACCEPT     tcp  --  virbr0 *       0.0.0.0/0            0.0.0.0/0            tcp dpt:53
3        0     0 ACCEPT     udp  --  virbr0 *       0.0.0.0/0            0.0.0.0/0            udp dpt:67
4        0     0 ACCEPT     tcp  --  virbr0 *       0.0.0.0/0            0.0.0.0/0            tcp dpt:67

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
num   pkts bytes target     prot opt in     out     source               destination         
1     589K 2304M ACCEPT     all  --  *      virbr0  0.0.0.0/0            192.168.122.0/24     state RELATED,ESTABLISHED
2     403K   24M ACCEPT     all  --  virbr0 *       192.168.122.0/24     0.0.0.0/0           
3        0     0 ACCEPT     all  --  virbr0 virbr0  0.0.0.0/0            0.0.0.0/0           
4        1    60 REJECT     all  --  *      virbr0  0.0.0.0/0            0.0.0.0/0            reject-with icmp-port-unreachable
5        0     0 REJECT     all  --  virbr0 *       0.0.0.0/0            0.0.0.0/0            reject-with icmp-port-unreachable

Chain OUTPUT (policy ACCEPT 4 packets, 480 bytes)

解決啦

我在nat表中添加了這2條規則：

$sudo iptables -t nat -A PREROUTING -p tcp --dport 2222 -j DNAT --to-destination 192.168.122.203:22
$sudo iptables -t nat -A POSTROUTING -p tcp --dport 22 -d 192.168.122.203 -j SNAT --to 192.168.122.1

然後我刪除了表格過濾器FORWARD鏈的規則4和5

$sudo iptables -nL -v --line-numbers -t filter

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
(...)        
4        7   420 REJECT     all  --  *      virbr0  0.0.0.0/0            0.0.0.0/0            reject-with icmp-port-unreachable
5        0     0 REJECT     all  --  virbr0 *       0.0.0.0/0            0.0.0.0/0            reject-with icmp-port-unreachable

$sudo iptables -D FORWARD 5 -t filter
$sudo iptables -D FORWARD 4 -t filter

現在，我通過執行以下操作連接到vm1：

$ssh user1@host -p 2222
user1@vm1:~$