Port forwarding with 2 interfaces not working

Question

I'm running debian and I've got the following network configuration:

eth0      Link encap:Ethernet
          inet addr:192.168.16.6  Bcast:192.168.16.255  Mask:255.255.255.0
          inet6 addr: fe80::204:75ff:fe9b:50e5/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:167010058 errors:0 dropped:0 overruns:1 frame:0
          TX packets:286396455 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:3019943786 (2.8 GiB)  TX bytes:161811580 (154.3 MiB)
          Interrupt:16 Base address:0x2c00

eth1      Link encap:Ethernet
          inet6 addr: fe80::202:55ff:fe07:6d6/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:276813626 errors:2444616 dropped:0 overruns:0 frame:0
          TX packets:87946731 errors:0 dropped:0 overruns:0 carrier:0
          collisions:2444616 txqueuelen:1000
          RX bytes:1634441886 (1.5 GiB)  TX bytes:2402441796 (2.2 GiB)
          Interrupt:29

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:16436  Metric:1
          RX packets:3896208 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3896208 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:828004427 (789.6 MiB)  TX bytes:828004427 (789.6 MiB)

ppp0      Link encap:Point-to-Point Protocol
          inet addr:XXX.XXX.XXX  P-t-P:XXX.XXX.XXX.XXX  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1492  Metric:1
          RX packets:3324045 errors:0 dropped:0 overruns:0 frame:0
          TX packets:740415 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:301507344 (287.5 MiB)  TX bytes:100747638 (96.0 MiB)

eth0 is for the local area network and eht1 is connected to a DSL modem. I wish to redirect all incoming traffic from internet (port 81) to a machine in my local area network (192.168.16.8:3000). I'm using ufw but I disabled it to work with a clean iptables. I'm planning to turn it on again after the configuration is done.

I tried this:

iptables -A PREROUTING -t nat -i eth1 -p tcp --dport 81 -j DNAT --to 192.168.16.8:3000
iptables -I FORWARD -p tcp --dport 81 -i eth1 -j ACCEPT
iptables -A INPUT -p tcp -m state --state NEW --dport 81 -i eth1 -j ACCEPT

But did not work! Here is the full log incuding an iptables -L: http://pastebin.com/5vXZ7pQu Here is an iptables-save log: http://pastebin.com/KPSCxL0x

Im using: net.ipv4.ip_forward = 1

Thanks!

score 0 · Accepted Answer · answered Sep 11 '14 at 19:53

0

Interface was incorrect, and this is how it goes:

iptables -t nat -i ppp0 -A PREROUTING -p tcp --dport 81 -j DNAT --to-destination 192.168.16.8:3000
iptables -t nat -A POSTROUTING -p tcp --dport 81 -j MASQUERADE

answered Sep 11 '14 at 19:53

Liam

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Port forwarding with 2 interfaces not working

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