iptables：伪装的端口转发不起作用

9

我的港口货运代理遇到了一些问题。NAT似乎可以正常工作，并且端口转发中的一个似乎可以正常工作（udp端口7887至计算机192.168.1.100）。但是其他人没有。

我怀疑这很重要，但是eth1和eth2位于双端口NIC上。

dhcp提供了WAN Internet访问，因此，如果可能，解决方案应独立于WAN_IP。

/opt/firewall.sh

#!/bin/sh

WAN="eth1"
LAN="eth2"

#ifconfig $LAN up
#ifconfig $LAN 192.168.1.1 netmask 255.255.255.0


echo 1 > /proc/sys/net/ipv4/ip_forward
sysctl -w net.ipv4.ip_forward=1

iptables -F
iptables -t nat -F
iptables -t mangle -F
iptables -X

iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP

iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT

iptables -A INPUT -i $LAN -j ACCEPT
iptables -A OUTPUT -o $WAN -j ACCEPT
iptables -A OUTPUT -o $LAN -j ACCEPT

iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

iptables -A FORWARD -o $LAN -m state --state ESTABLISHED,RELATED -j ACCEPT

iptables -A FORWARD -i $LAN -o $WAN -j ACCEPT
iptables -t nat -A POSTROUTING -o $WAN -j MASQUERADE

# Allow ICMP echo reply/destination unreachable/time exceeded.
iptables -A INPUT -p icmp --icmp-type 0 -j ACCEPT
iptables -A INPUT -p icmp --icmp-type 3 -j ACCEPT
iptables -A INPUT -p icmp --icmp-type 11 -j ACCEPT

# SSH
iptables -t nat -A PREROUTING -p tcp -i $WAN -m multiport --dports 22 -j DNAT --to 192.168.1.250
iptables -A FORWARD -p tcp -i $WAN -o $LAN -d 192.168.1.250 -m multiport --dports 22 -j ACCEPT

# WWW
iptables -t nat -A PREROUTING -p tcp -i $WAN -m multiport --dports 80,443 -j DNAT --to 192.168.1.99
iptables -A FORWARD -p tcp -i $WAN -o $LAN -d 192.168.1.99 -m multiport --dports 80,443 -j ACCEPT

# TOR
iptables -t nat -A PREROUTING -p tcp -i $WAN -m multiport --dports 9001,9030 -j DNAT --to 192.168.1.250
iptables -A FORWARD -p tcp -i $WAN -o $LAN -d 192.168.1.250 -m multiport --dports 9001,9030 -j ACCEPT

# I2P
iptables -t nat -A PREROUTING -p tcp -i $WAN -m multiport --dports 7887 -j DNAT --to 192.168.1.100
iptables -A FORWARD -p tcp -i $WAN -o $LAN -d 192.168.1.100 -m multiport --dports 7887 -j ACCEPT
iptables -t nat -A PREROUTING -p udp -i $WAN -m multiport --dports 7887 -j DNAT --to 192.168.1.100
iptables -A FORWARD -p udp -i $WAN -o $LAN -d 192.168.1.100 -m multiport --dports 7887 -j ACCEPT

iptables -t nat -A PREROUTING -p tcp -i $WAN -m multiport --dports 8887 -j DNAT --to 192.168.1.250
iptables -A FORWARD -p tcp -i $WAN -o $LAN -d 192.168.1.250 -m multiport --dports 8887 -j ACCEPT
iptables -t nat -A PREROUTING -p udp -i $WAN -m multiport --dports 8887 -j DNAT --to 192.168.1.250
iptables -A FORWARD -p udp -i $WAN -o $LAN -d 192.168.1.250 -m multiport --dports 8887 -j ACCEPT

iptables -t nat -L -v

Chain PREROUTING (policy ACCEPT 1047K packets, 80M bytes)
 pkts bytes target     prot opt in     out     source               destination         
    5   232 DNAT       tcp  --  eth1   any     anywhere             anywhere            multiport dports ssh to:192.168.1.250 
    1    60 DNAT       tcp  --  eth1   any     anywhere             anywhere            tcp dpt:www to:192.168.1.99:80 
    0     0 DNAT       tcp  --  eth1   any     anywhere             anywhere            multiport dports 9001,9030 to:192.168.1.250 
    0     0 DNAT       tcp  --  eth1   any     anywhere             anywhere            multiport dports 7887 to:192.168.1.100 
12166 4042K DNAT       udp  --  eth1   any     anywhere             anywhere            multiport dports 7887 to:192.168.1.100 
    0     0 DNAT       tcp  --  eth1   any     anywhere             anywhere            multiport dports 8887 to:192.168.1.250 
    0     0 DNAT       udp  --  eth1   any     anywhere             anywhere            multiport dports 8887 to:192.168.1.250 

Chain POSTROUTING (policy ACCEPT 12313 packets, 4085K bytes)
 pkts bytes target     prot opt in     out     source               destination         
 637K   46M MASQUERADE  all  --  any    eth1    anywhere             anywhere            

Chain OUTPUT (policy ACCEPT 395 packets, 62752 bytes)
 pkts bytes target     prot opt in     out     source               destination

iptables -L -v

Chain INPUT (policy DROP 9336 packets, 846K bytes)
 pkts bytes target     prot opt in     out     source               destination         
    1    76 ACCEPT     all  --  lo     any     anywhere             anywhere            
  467 55711 ACCEPT     all  --  eth2   any     anywhere             anywhere            
   64  5598 ACCEPT     all  --  any    any     anywhere             anywhere            state RELATED,ESTABLISHED 
    0     0 ACCEPT     icmp --  any    any     anywhere             anywhere            icmp echo-reply 
   18  1796 ACCEPT     icmp --  any    any     anywhere             anywhere            icmp destination-unreachable 
    0     0 ACCEPT     icmp --  any    any     anywhere             anywhere            icmp time-exceeded 

Chain FORWARD (policy DROP 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
60586   29M ACCEPT     all  --  any    eth2    anywhere             anywhere            state RELATED,ESTABLISHED 
70888  126M ACCEPT     all  --  eth2   eth1    anywhere             anywhere            
    0     0 ACCEPT     tcp  --  eth1   eth2    anywhere             192.168.1.250       multiport dports ssh 
    0     0 ACCEPT     tcp  --  any    any     anywhere             192.168.1.99        tcp dpt:www state NEW,RELATED,ESTABLISHED 
    0     0 ACCEPT     tcp  --  eth1   eth2    anywhere             192.168.1.250       multiport dports 9001,9030 
    0     0 ACCEPT     tcp  --  eth1   eth2    anywhere             192.168.1.100       multiport dports 7887 
  646  310K ACCEPT     udp  --  eth1   eth2    anywhere             192.168.1.100       multiport dports 7887 
    0     0 ACCEPT     tcp  --  eth1   eth2    anywhere             192.168.1.250       multiport dports 8887 
    0     0 ACCEPT     udp  --  eth1   eth2    anywhere             192.168.1.250       multiport dports 8887 

Chain OUTPUT (policy DROP 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
  157 13421 ACCEPT     all  --  any    lo      anywhere             anywhere            
   76  9678 ACCEPT     all  --  any    eth1    anywhere             anywhere            
  159 26706 ACCEPT     all  --  any    eth2    anywhere             anywhere

存取测试：

 me@external-host $ ssh WAN_IP        
 ssh: connect to host WAN_IP port 22: Connection timed out

 me@external-host $ wget WAN_IP                
 --2012-05-06 15:46:50--  http://WAN_IP/
 Connecting to |WAN_IP|:80... failed: Connection timed out.

访问测试日志：

 May  8 21:04:18 router kernel: [11692.837693] FOWARD: IN=eth1 OUT=eth2 SRC=130.235.35.233 DST=192.168.1.99 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=35931 DF PROTO=TCP SPT=52319 DPT=80 WINDOW=14600 RES=0x00 SYN URGP=0 
 May  8 21:04:19 router kernel: [11693.837174] FOWARD: IN=eth1 OUT=eth2 SRC=130.235.35.233 DST=192.168.1.99 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=24784 DF PROTO=TCP SPT=52320 DPT=80 WINDOW=14600 RES=0x00 SYN URGP=0 
 May  8 21:04:20 router kernel: [11694.835943] FOWARD: IN=eth1 OUT=eth2 SRC=130.235.35.233 DST=192.168.1.99 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=57280 DF PROTO=TCP SPT=52321 DPT=80 WINDOW=14600 RES=0x00 SYN URGP=0 
 May  8 21:04:21 router kernel: [11695.835159] FOWARD: IN=eth1 OUT=eth2 SRC=130.235.35.233 DST=192.168.1.99 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=10721 DF PROTO=TCP SPT=52322 DPT=80 WINDOW=14600 RES=0x00 SYN URGP=0 
 May  8 21:04:22 router kernel: [11696.833763] FOWARD: IN=eth1 OUT=eth2 SRC=130.235.35.233 DST=192.168.1.99 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=19002 DF PROTO=TCP SPT=52323 DPT=80 WINDOW=14600 RES=0x00 SYN URGP=0 
 May  8 21:04:23 router kernel: [11697.832960] FOWARD: IN=eth1 OUT=eth2 SRC=130.235.35.233 DST=192.168.1.99 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=17468 DF PROTO=TCP SPT=52324 DPT=80 WINDOW=14600 RES=0x00 SYN URGP=0 
 May  8 21:04:24 router kernel: [11698.831733] FOWARD: IN=eth1 OUT=eth2 SRC=130.235.35.233 DST=192.168.1.99 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=32834 DF PROTO=TCP SPT=52325 DPT=80 WINDOW=14600 RES=0x00 SYN URGP=0 
 May  8 21:04:25 router kernel: [11699.830620] FOWARD: IN=eth1 OUT=eth2 SRC=130.235.35.233 DST=192.168.1.99 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=28252 DF PROTO=TCP SPT=52326 DPT=80 WINDOW=14600 RES=0x00 SYN URGP=0 
 May  8 21:04:26 router kernel: [11700.829493] FOWARD: IN=eth1 OUT=eth2 SRC=130.235.35.233 DST=192.168.1.99 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=43537 DF PROTO=TCP SPT=52327 DPT=80 WINDOW=14600 RES=0x00 SYN URGP=0 
 May  8 21:04:27 router kernel: [11701.829118] FOWARD: IN=eth1 OUT=eth2 SRC=130.235.35.233 DST=192.168.1.99 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=55720 DF PROTO=TCP SPT=52328 DPT=80 WINDOW=14600 RES=0x00 SYN URGP=0
iptables  nat  port-forwarding 
— 罗伯特·福斯
source
您可以通过添加类似于iptables -I INPUT 1 -i $LAN -j LOG调试问题的规则来启用日志记录
— 2012年
您应该检查过滤器表中的计数器，以查看是否有任何符合您的接受规则的事件。
— Falcon Momot
@FalconKirtaran，我用接受规则计数器更新了问题。
— 罗伯特·佛斯
您可能想要在FORWARD链（iptables -A FORWARD -j LOG）的末尾添加一条日志行，以查看它是否被丢弃。
— 安迪·史密斯
正如我所怀疑的那样，他们没有达到接受规则。但是，它们甚至根本没有触及过滤器中的前向链（因为那里也没有丢弃的数据包）。
— Falcon Momot 2012年

Answers:

3

原来，一台内部计算机已关闭，并且我的WAN_IP已更改（由于dhcp）。

在进行故障排除期间，我对脚本进行了一些改进，现在该脚本可以正常运行，而不必花哨。随意抓取副本！

/opt/firewall.sh

#!/bin/sh

WAN="eth1"
LAN="eth2"

#ifconfig $LAN up
#ifconfig $LAN 192.168.1.1 netmask 255.255.255.0

echo 1 > /proc/sys/net/ipv4/ip_forward
sysctl -w net.ipv4.ip_forward=1

iptables -F
iptables -t nat -F
iptables -t mangle -F
iptables -X

#
# Debug logging
#iptables -I INPUT 1 --source 130.235.35.233/31 -j LOG --log-prefix "INPUT: "
#iptables -I FORWARD 1 --source 130.235.35.233/31 -j LOG --log-prefix "FOWARD: "


#
# Default to drop packets
iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP

#
# Allow all local loopback traffic
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT

#
# Allow output on $WAN and $LAN if. Allow input on $LAN if.
iptables -A INPUT -i $LAN -j ACCEPT
iptables -A OUTPUT -o $WAN -j ACCEPT
iptables -A OUTPUT -o $LAN -j ACCEPT

iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

iptables -A FORWARD -o $LAN -m state --state ESTABLISHED,RELATED -j ACCEPT

iptables -A FORWARD -i $LAN -o $WAN -j ACCEPT
iptables -t nat -A POSTROUTING -o $WAN -j MASQUERADE

# Allow ICMP echo reply/echo request/destination unreachable/time exceeded
iptables -A INPUT -p icmp --icmp-type destination-unreachable -j ACCEPT
iptables -A INPUT -p icmp --icmp-type time-exceeded -j ACCEPT
iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
iptables -A INPUT -p icmp --icmp-type echo-reply -j ACCEPT

# SSH
iptables -t nat -A PREROUTING -p tcp -i $WAN -m multiport --dports 22 -j DNAT --to 192.168.1.250
iptables -A FORWARD -p tcp -i $WAN -o $LAN -d 192.168.1.250 -m multiport --dports 22 -j ACCEPT

# WWW
iptables -t nat -A PREROUTING -p tcp -i $WAN -m multiport --dports 80,443 -j DNAT --to 192.168.1.99
iptables -A FORWARD -p tcp -i $WAN -o $LAN -d 192.168.1.99 -m multiport --dports 80,443 -j ACCEPT

# TOR
iptables -t nat -A PREROUTING -p tcp -i $WAN -m multiport --dports 9001,9030 -j DNAT --to 192.168.1.250
iptables -A FORWARD -p tcp -i $WAN -o $LAN -d 192.168.1.250 -m multiport --dports 9001,9030 -j ACCEPT

# I2P
iptables -t nat -A PREROUTING -p tcp -i $WAN -m multiport --dports 7887 -j DNAT --to 192.168.1.100
iptables -A FORWARD -p tcp -i $WAN -o $LAN -d 192.168.1.100 -m multiport --dports 7887 -j ACCEPT
iptables -t nat -A PREROUTING -p udp -i $WAN -m multiport --dports 7887 -j DNAT --to 192.168.1.100
iptables -A FORWARD -p udp -i $WAN -o $LAN -d 192.168.1.100 -m multiport --dports 7887 -j ACCEPT

iptables -t nat -A PREROUTING -p tcp -i $WAN -m multiport --dports 8887 -j DNAT --to 192.168.1.250
iptables -A FORWARD -p tcp -i $WAN -o $LAN -d 192.168.1.250 -m multiport --dports 8887 -j ACCEPT
iptables -t nat -A PREROUTING -p udp -i $WAN -m multiport --dports 8887 -j DNAT --to 192.168.1.250
iptables -A FORWARD -p udp -i $WAN -o $LAN -d 192.168.1.250 -m multiport --dports 8887 -j ACCEPT


exit 0 #report success
— 罗伯特·福斯
source
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