linux – 传入的数据包没有命中iptables INPUT链

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我在docker容器中运行VPN客户端.我正在尝试通过端口8080从主机连接到在docker容器中运行的Web服务器.当我尝试连接时,我通过tcpdump在端口8080上看到我的传入数据包,但Web服务器从未看到它.
我已经为数据包的所有可能状态转换添加了iptables’-j LOG’规则,试图追踪它.我看到的数据包是:

>表’raw’,链PREROUTING
>表’mangle’,链PREROUTING
> table’nat’,链条PREROUTING

然后……没什么.在一小段延迟之后,数据包被重新发送,我看到新数据包通过PREROUTING.没有任何东西出现在剪辑INPUT或mangle FORWARD链上 – 据我所知,这是不可能的 – 它必须击中其中一个.
有没有办法让数据包通过PREROUTING,但不能点击INPUT或FORWARD?
我的iptables如下:

root@87ff7ad8e4f9:/# iptables -t raw -L 
Chain PREROUTING (policy ACCEPT)
target     prot opt source               destination         
NFLOG      tcp  --  anywhere             anywhere             tcp spt:http-alt nflog-prefix  "raw pre-route Src incoming packet"
NFLOG      tcp  --  anywhere             anywhere             tcp dpt:http-alt nflog-prefix  "raw pre-route Dest incoming packet"

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
NFLOG      tcp  --  anywhere             anywhere             tcp dpt:http-alt nflog-prefix  "Dest outgoing packet"
NFLOG      tcp  --  anywhere             anywhere             tcp spt:http-alt nflog-prefix  "Src outgoing packet"
root@87ff7ad8e4f9:/# iptables -t mangle -L 
Chain PREROUTING (policy ACCEPT)
target     prot opt source               destination         
NFLOG      tcp  --  anywhere             anywhere             tcp dpt:http-alt nflog-prefix  "mangle PREROUTING Dest incoming packet"

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
NFLOG      all  --  anywhere             anywhere             nflog-prefix  "mangle INPUT Dest incoming packet any2"

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         
NFLOG      all  --  anywhere             anywhere             nflog-prefix  "mangle FORWARD Dest incoming packet any"

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
MARK       tcp  --  anywhere             anywhere             tcp spt:http-alt MARK set 0x1
MARK       tcp  --  anywhere             anywhere             tcp dpt:http-alt MARK set 0x1
NFLOG      tcp  --  anywhere             anywhere             tcp spt:http-alt nflog-prefix  "MARK set 0x1"
NFLOG      tcp  --  anywhere             anywhere             tcp dpt:http-alt nflog-prefix  "Dest MARK set 0x1"

Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination         
root@87ff7ad8e4f9:/# iptables -t nat -L 
Chain PREROUTING (policy ACCEPT)
target     prot opt source               destination         
NFLOG      tcp  --  anywhere             anywhere             tcp dpt:http-alt nflog-prefix  "nat PREROUTING Dest incoming packet"

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
NFLOG      tcp  --  anywhere             anywhere             tcp dpt:http-alt nflog-prefix  "nat INPUT Dest incoming packet"

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         

Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination         
root@87ff7ad8e4f9:/# iptables -t filter -L 
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
NFLOG      tcp  --  anywhere             anywhere             nflog-prefix  "connection made"
NFLOG      tcp  --  anywhere             anywhere             tcp dpt:http-alt nflog-prefix  "filter INPUT Dest incoming packet"

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     all  --  anywhere             anywhere             ctstate RELATED,ESTABLISHED
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             172.17.0.0/16       
ACCEPT     udp  --  anywhere             anywhere             udp dpt:domain
ACCEPT     tcp  --  anywhere             anywhere             owner GID match vpn
ACCEPT     udp  --  anywhere             anywhere             owner GID match vpn
DROP       all  --  anywhere             anywhere

我的系统日志显示

Oct  4 07:22:56 87ff7ad8e4f9 raw pre-route Dest incoming packet IN=eth0 OUT= MAC=02:42:ac:11:00:02:02:42:2e:2c:fd:2e:08:00 SRC=76.167.254.196 DST=172.17.0.2 LEN=60 TOS=00 PREC=0x00 TTL=63 ID=39119 DF PROTO=TCP SPT=46644 DPT=8080 SEQ=4027056663 ACK=0 WINDOW=29200 SYN URGP=0 MARK=0 
Oct  4 07:22:56 87ff7ad8e4f9 mangle PREROUTING Dest incoming packet IN=eth0 OUT= MAC=02:42:ac:11:00:02:02:42:2e:2c:fd:2e:08:00 SRC=76.167.254.196 DST=172.17.0.2 LEN=60 TOS=00 PREC=0x00 TTL=63 ID=39119 DF PROTO=TCP SPT=46644 DPT=8080 SEQ=4027056663 ACK=0 WINDOW=29200 SYN URGP=0 MARK=0 
Oct  4 07:22:56 87ff7ad8e4f9 nat PREROUTING Dest incoming packet IN=eth0 OUT= MAC=02:42:ac:11:00:02:02:42:2e:2c:fd:2e:08:00 SRC=76.167.254.196 DST=172.17.0.2 LEN=60 TOS=00 PREC=0x00 TTL=63 ID=39119 DF PROTO=TCP SPT=46644 DPT=8080 SEQ=4027056663 ACK=0 WINDOW=29200 SYN URGP=0 MARK=0 
Oct  4 07:22:57 87ff7ad8e4f9 raw pre-route Dest incoming packet IN=eth0 OUT= MAC=02:42:ac:11:00:02:02:42:2e:2c:fd:2e:08:00 SRC=76.167.254.196 DST=172.17.0.2 LEN=60 TOS=00 PREC=0x00 TTL=63 ID=39120 DF PROTO=TCP SPT=46644 DPT=8080 SEQ=4027056663 ACK=0 WINDOW=29200 SYN URGP=0 MARK=0 
Oct  4 07:22:57 87ff7ad8e4f9 mangle PREROUTING Dest incoming packet IN=eth0 OUT= MAC=02:42:ac:11:00:02:02:42:2e:2c:fd:2e:08:00 SRC=76.167.254.196 DST=172.17.0.2 LEN=60 TOS=00 PREC=0x00 TTL=63 ID=39120 DF PROTO=TCP SPT=46644 DPT=8080 SEQ=4027056663 ACK=0 WINDOW=29200 SYN URGP=0 MARK=0 
Oct  4 07:22:57 87ff7ad8e4f9 nat PREROUTING Dest incoming packet IN=eth0 OUT= MAC=02:42:ac:11:00:02:02:42:2e:2c:fd:2e:08:00 SRC=76.167.254.196 DST=172.17.0.2 LEN=60 TOS=00 PREC=0x00 TTL=63 ID=39120 DF PROTO=TCP SPT=46644 DPT=8080 SEQ=4027056663 ACK=0 WINDOW=29200 SYN URGP=0 MARK=0

解决方法

我想我明白了.
PREROUTING和INPUT / FORWARD之间有什么关系?看看 the map:路由决策.

从您的日志:SRC = 76.167.254.196 DST = 172.17.0.2.
没有DNAT,您无法将公共路由到私有IP地址.尝试添加

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 8080 -j DNAT --to-destination 172.17.0.2

或者您可以将VPN设置为拥有私有IP.

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