Question

Help with iptables in OpenWRT

Asked by: ykravchenko

I need some help configuring iptables or the VPN Concentrator 3000...

I have an OpenWRT Linux that I have configured with vpnc to connect to my VPN Concentrator.  When I connect, I can ping the IP address assigned to the Linux box, and I can access everything on the network via the VPN tunnel.  So far, so good.

Now, I am trying to route packets that come to the address assigned by the VPN to a device on the inside of the remote network, and I am having difficulties getting that accomplished.  Here is my network configuration:

root@OpenWrt:/etc# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:16:01:D1:58:FC
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:14689 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8248 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:2846763 (2.7 MiB)  TX bytes:2779452 (2.6 MiB)
          Interrupt:4

eth0.0    Link encap:Ethernet  HWaddr 00:16:01:D1:58:FC
          inet addr:172.16.1.1  Bcast:172.16.1.7  Mask:255.255.255.248
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:143 errors:0 dropped:0 overruns:0 frame:0
          TX packets:155 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:16392 (16.0 KiB)  TX bytes:19718 (19.2 KiB)

eth0.1    Link encap:Ethernet  HWaddr 00:16:01:D1:58:FC
          inet addr:66.XX.XX.133  Bcast:66.XX.XX.255  Mask:255.255.254.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:11820 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8100 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:2258755 (2.1 MiB)  TX bytes:2726040 (2.5 MiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:2 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:242 (242.0 B)  TX bytes:242 (242.0 B)

tun0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
          inet addr:10.200.202.10  P-t-P:10.200.202.10  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1412  Metric:1
          RX packets:8949 errors:0 dropped:0 overruns:0 frame:0
          TX packets:7966 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:10
          RX bytes:1311996 (1.2 MiB)  TX bytes:2076363 (1.9 MiB)

Here is the iptables configuration:

root@OpenWrt:/etc# iptables -L -n -v
Chain INPUT (policy DROP 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination
    0     0 DROP       all  --  *      *       0.0.0.0/0            0.0.0.0/0           state INVALID
 1644  173K ACCEPT     all  --  *      *       0.0.0.0/0            0.0.0.0/0           state RELATED,ESTABLISHED
    0     0 DROP       tcp  --  *      *       0.0.0.0/0            0.0.0.0/0           tcp option=!2 flags:0x02/0x02
    9  4179 input_rule  all  --  *      *       0.0.0.0/0            0.0.0.0/0
    9  4179 input_wan  all  --  eth0.1 *       0.0.0.0/0            0.0.0.0/0
    9  4179 LAN_ACCEPT  all  --  *      *       0.0.0.0/0            0.0.0.0/0
    0     0 ACCEPT     icmp --  *      *       0.0.0.0/0            0.0.0.0/0
    0     0 ACCEPT     47   --  *      *       0.0.0.0/0            0.0.0.0/0
    0     0 REJECT     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0           reject-with tcp-reset
    9  4179 REJECT     all  --  *      *       0.0.0.0/0            0.0.0.0/0           reject-with icmp-port-unreachable

Chain FORWARD (policy DROP 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination
    0     0 DROP       all  --  *      *       0.0.0.0/0            0.0.0.0/0           state INVALID
    0     0 TCPMSS     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0           tcp flags:0x06/0x02 TCPMSS clamp to PMTU
    0     0 ACCEPT     all  --  *      *       0.0.0.0/0            0.0.0.0/0           state RELATED,ESTABLISHED
    0     0 forwarding_rule  all  --  *      *       0.0.0.0/0            0.0.0.0/0
    0     0 forwarding_wan  all  --  eth0.1 *       0.0.0.0/0            0.0.0.0/0
    0     0 ACCEPT     all  --  eth0.0 eth0.0  0.0.0.0/0            0.0.0.0/0
    0     0 ACCEPT     all  --  eth0.0 eth0.1  0.0.0.0/0            0.0.0.0/0

Chain OUTPUT (policy DROP 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination
    0     0 DROP       all  --  *      *       0.0.0.0/0            0.0.0.0/0           state INVALID
 2315 1275K ACCEPT     all  --  *      *       0.0.0.0/0            0.0.0.0/0           state RELATED,ESTABLISHED
    0     0 output_rule  all  --  *      *       0.0.0.0/0            0.0.0.0/0
    0     0 ACCEPT     all  --  *      *       0.0.0.0/0            0.0.0.0/0
    0     0 REJECT     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0           reject-with tcp-reset
    0     0 REJECT     all  --  *      *       0.0.0.0/0            0.0.0.0/0           reject-with icmp-port-unreachable

Chain LAN_ACCEPT (1 references)
 pkts bytes target     prot opt in     out     source               destination
    9  4179 RETURN     all  --  eth0.1 *       0.0.0.0/0            0.0.0.0/0
    0     0 ACCEPT     all  --  *      *       0.0.0.0/0            0.0.0.0/0

Chain forwarding_rule (1 references)
 pkts bytes target     prot opt in     out     source               destination

Chain forwarding_wan (1 references)
 pkts bytes target     prot opt in     out     source               destination

Chain input_rule (1 references)
 pkts bytes target     prot opt in     out     source               destination

Chain input_wan (1 references)
 pkts bytes target     prot opt in     out     source               destination

Chain output_rule (1 references)
 pkts bytes target     prot opt in     out     source               destination

Any help would be much appreciated.

Thank you,

Yan Kravchenko

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Asked On
2007-09-11 at 15:31:27ID22821980
Tags

openwrt

,

iptables

Topics

Network Routers

,

Networking Hardware Firewalls

,

Linux Networking

Participating Experts
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Points
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Comments
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Answers

 

by: RedimidoPosted on 2007-09-11 at 20:41:17ID: 19873747

if you want to route to your internal network, then it is easier to modify your openvpn config file to route the internal network thru that connection.

more about that at:
http://openvpn.net/howto.html#scope
and maybe with tap (bridging)
http://www.linux.com/feature/58336

or perhaps you want to nat your client?

 

by: ykravchenkoPosted on 2007-09-11 at 21:42:35ID: 19873939

The reason I went with vpnc is because the locations where OpenWRT are installed will not have a static IP address.  When I looked at typical Ipsec Lan-to-Lan solutions, they all required a static IP address.  Am I wrong about that?  Is there a way to set-up a Lan-to-Lan without a static IP on both ends?

 

by: RedimidoPosted on 2007-09-11 at 23:43:53ID: 19874290

you are using in fact OpenVPN, which works pretty well with dynamic ip's,
even on both sides =)

see
"What is the set of options needed to dig a tunnel between two gateways connected to the Internet with a pppoe connection (ip addresses very volatile). The documentation specifies that it's possible to use such a setup but I couldn't find exactly which options are needed."

http://openvpn.net/faq.html

vpnc is just a client. its a wrapper over openvpn acting as a client.

20120131-EE-VQP-002

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