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I'm trying to route packets between a wired-wireless-wired link. I'm using a Spirent test center as a traffic generator which routes traffic to an Access point over a LAN cable(wired link)- This Access point then routes this traffic to a windows laptop (wireless Link)which in turn must route the packet back to the Spirent test center(wired link).

The 1st port of Spirent has an IP of 192.168.1.200 and its default gateway is the IP of the access point 192.168.1.1 . Both the wired and wireless interfaces of Access Point have the same IP that is 192.168.1.1 . The ip address of the WiFi interface of the laptop is 192.168.1.163 and the Ip of the ethernet interface(connected to Spirent) is 192.168.1.165. The other port on Spirent has an IP of 192.168.3.200 and its default gateway is 192.168.1.165.

The routing table of the AP is as follows:- routes ap. The routing table of the laptop is :-routes laptop

I can't send traffic from end to end. The traffic reaches the wireless interface (.1.163) of the laptop but not the wired interface( .1.165). I tried to bridge it but it didn't work. So I disabled the bridge and set separate IPs to both the interfaces of the laptop and assigned static routes. But it still doesn't work.

EDIT1:- I bridged the interfaces of the laptop with an IP of 192.168.1.170. Now I can't ping the 2nd port of the Spirent (.3.220) at all! I could add a static route to the laptop but because the WiFi interfaces are bridged ( and therefore have the same IP and the same IF number), I dont know what default gateway or what outgoing Interface to provide.

pbalraj
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  • You can't bridge a wired interface to a wireless client. You will need to find some other way to structure your network. – Michael Hampton Jul 20 '16 at 17:14
  • I'm trying to bridge the wireless and wired interface of the same laptop. I know windows offers this functionality, but I cant route the packets between the 2 interfaces – pbalraj Jul 20 '16 at 17:21
  • I'm confused. Are you trying to route, or are you trying to bridge? You wrote that you need to route, but they are completely separate concepts. Routing sends traffic between different networks, while bridging works on the same network. – Ron Maupin Jul 20 '16 at 17:21
  • @RonMaupin - I'm actually okay with either bridging or routing provided they pass traffic to 192.168.3.200 which is the endpoint. I tried to bridge the 2 interface 192.168.1.163 and 192.168.1.165 and assigned a static route -p add 192.168.3.200 mask 255.255.255.0 192.168.3.200 . But that didnt work – pbalraj Jul 20 '16 at 17:24
  • If you are bridging, you can't have the same source and destination MAC address on the frame, and routing will not work with the same source and destination IP address on the packet. You need to have a different destination interface from the source interface. That means that you need two interfaces on your traffic generator is you want it to be both the source and destination device. – Ron Maupin Jul 20 '16 at 17:27
  • @RonMaupin The traffic generator does have 2 emulated devices with different ips and Mac addresses. – pbalraj Jul 20 '16 at 17:36
  • @RonMaupin Device 1 has an Ip of 192.168.1.200 and device 2 has an ip of 192.168.3.200. Each have a different MAC . In an earlier comment you said bridging works only on the same network, so should I change the IP of device 2 to include it in the .1 subnet? – pbalraj Jul 20 '16 at 17:38
  • The interfaces are on two separate networks, so you need a router to route between the networks. You cannot bridge between separate networks. A host sending traffic to an IP address on a different network will send the traffic to its configured gateway, and, presumably, the gateway has a route to the destination network. – Ron Maupin Jul 20 '16 at 17:39
  • @RonMaupin I could try two things 1. Enable Internet Connection Sharing( that was the first result when I googled how to use your laptop as a router) 2. Scrap Bridging completely and rely on static routes to forward the traffic. – pbalraj Jul 20 '16 at 17:55
  • The only issue with 2. is that I can't ping the final device 192.168.3.200 from my AP. So I am probably going wrong in assigning the default gateway in my route – pbalraj Jul 20 '16 at 17:56
  • I think ICS will go from wired to wireless. You simply don't bridge two different networks. What is the configured gateway for your source interface (the traffic generator or the WAP)? That is where the traffic will be sent since the destination is on a different network. – Ron Maupin Jul 20 '16 at 17:57
  • gateway for the source interface is the WAP – pbalraj Jul 20 '16 at 17:58
  • As a gateway. the WAP must know how to get to both networks. The gateway must know where to send traffic for the foreign network. It is a bridge, not a router. You need a router. – Ron Maupin Jul 20 '16 at 19:56

1 Answers1

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Linux Ethernet/wireless bridging

It seems you really cant bridge a wifi interface. One user suggested giving the wired interface an IP that is a subset of the wifi interface subnet . Maybe I will try that .

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pbalraj
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