If the cable you normally have is a crossover, it should be marked as such. Did you make it yourself in days gone by? Sometimes they are printed on the cable "crossover" or they have a special colored band on each end near the connector. You can also put the two ends together and compare the wire color order (the end should be clear). If they are in the same order, then it is normal (straight thru, if several seem mixed up, then it is a crossover.

I don't see why your setup with the hub or switch wouldn't work. Probably a hub is better since all ports receive the same messages. Then you need to put a PC with Linux in there on the hub, with at least one network card in promiscuous mode. Google that and you will find out how to do it. There are then several tools that you can use to sniff. Snort, ethereal, snarf, etc., Google TCP/IP traffic sniffing.

One thing I just thought of. The packets coming in to the router may be in chunks like frames. Your standard PC NIC may not be able to decode them. I reserve the right to be wrong and admit it in an open forum. You have some research ahead of you anyway.

-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of crash3m Sent: Thursday, June 02, 2005 1:06 PM To: [email protected] Subject: Re: quick network engineering review question

Maybe if you explained why you need to sniff the traffic someone could offer a solution. Maybe your answer can be solved by sniffing on the 'internal' side of the CSU/DSU.

On 6/1/05, David Nicol [email protected] wrote:

...

I want to sniff all traffic on the upstream link at my

installation. I have a

...

wire that comes into my Cisco router from the CSU/DSU. The

question is,

...

is this wire a normal Ethernet wire, so that I could plug it

into a hub and plug

...

the hub into the Cisco, that is, put a hub in line with it,

or is it something

...

else?

I already have the crossover cable for the new connection,

if plugging the

...

CSU/DSU wire into a hub is in fact copasetic.

Please reply on or off list as appropriate

-- David L Nicol Twinkies and Wonderbread are mainstream Americana