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Newbie alert with no TCP/IP knowledge... I am trying to set up a production test rig for testing an embedded 6-way ethernet switch by populating an XP PC with 6 NIC cards. I've started with two NICs just to prove the point, both on the same subnet, manual IP addresses of 172.16.0.1 / 172.16.0.2. The routing table (route print) shows (I believe) two loopback entries :

=====================================================
172.16.0.0     255.255.255.0    172.16.0.1  172.16.0.1
172.16.0.0     255.255.255.0    172.16.0.2  172.16.0.2
172.16.0.1     255.255.255.255  127.0.0.1   127.0.0.1
172.16.0.2     255.255.255.255  127.0.0.1   127.0.0.1
172.16.255.255 255.255.255.255  172.16.0.1  172.16.0.1
172.16.255.255 255.255.255.255  172.16.0.2  172.16.0.2
=====================================================

I would like to remove the loopback entries and replace them with "always external" routing entries.. i.e. if you ping 172.16.0.1 the packets use adapter 172.16.0.2, and are routed by the switch back to 172.16.0.1 and if you ping 172.16.0.2 the packets leave 172.16.0.1, and get routed by the switch back to 172.16.0.2, thereby doing a rudimentary connectivity test of the cables, the switch IC, magnetics etc.

A command of : route add 172.16.0.1 mask 255.255.255.255 172.16.0.2 (which seems to me to be uniquely specifying the use of 172.16.0.2 to send packets to a destination 172.16.0.1) fails with "The route addition failed: The route parameter is incorrect"

While : route add 172.16.0.2 mask 255.255.255.255 172.16.0.1 is accepted but I can't then ping 172.16.0.2

I did find some really good explanations in your old posts of meanings of each line in the table, but I'm obviously not quite understanding what is going on. I'm slightly concerned that the auto-generate route table has specified two adapters as gateways, but I don't know enough to understand the implications.

Ultimately, with 6 NICs in the box, I'd like to be able to make a table that will enable me to exercise every port on the switch.

many thanks David

David Bleloch
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1 Answers1

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You can use ping to do this. First setup the NICs to have static IP addresses. I'll give you an example with 2 NICs. NIC1 is set to 192.168.0.2 and NIC2 is 192.168.0.1. Then run the command:

ping 192.168.0.2 –s 192.168.0.1 –t

I think you'll find that if you unplug the external loopback cable the test will fail and if you plug it back in again, it will pass. For more help on ping, type ping -?

You may have to disable Windows Firewall to let the ping traffic through.

Gabriel
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