monitor port is in down state

[gmail2]

Hi All

I have an old Catalyst 2950 that I'm trying to use for some testing. I want to capture some traffic coming from a video conference to find out what it's doing.

I configured a monitor port using the command below

monitor session 1 source interface FastEthernet 0/2 - 24 both
monitor session 2 destination interface FastEthernet 0/1

However, doing so brings fa0/1 down. When I checked the document below, it says that this is by design to show that the port cannot be used for production.

However ... is any device supposed to monitor traffic on that port if the switch marks it as down !!??

http://www.cisco.com/en/US/products/hw/switches/ps708/products_tech_note09186a008015c612.shtml

I can apprecite that the switch and the firmware are old a little old (IOS 12.1) but can anybody give me any explanation as to why this is ?

I have used monitor port option on ProCurve switches before and it worked absolutely fine.

Thanks in advance for any help

Irish Poetry - Karen O'Connor
Irish Poetry and Short Stories - Doghouse Books
Garten und Landschaftsbau

 

[VinceWhirlwind]

Shouldn't your 2nd line read "monitor session 1 ..."?

 

[gmail2]

oops sorry ... yea, the actual config does say session 1 ... just a typo on the forum !

Irish Poetry - Karen O'Connor
Irish Poetry and Short Stories - Doghouse Books
Garten und Landschaftsbau

 

[VinceWhirlwind]

OK, well the "destination interface" actually kind-of disables the port as a switchport, but the port should still come up when you patch a device into it, to enable you to capture packets.

 

[vipergg]

That is the normal mode when you configure a port for a span session , it will show the port as down .

 

[gmail2]

Thanks for the replies guys, but the the port doesn't come up when I attach a device - it stays down. It's not "admin down" either (all though I did try the no shutdown command to no avail)

the documentation just says that this is by design but no explanation why. I don't see how you could use the port to monitor traffic if it always stays down !!??

Irish Poetry - Karen O'Connor
Irish Poetry and Short Stories - Doghouse Books
Garten und Landschaftsbau

 

[gmail2]

OK ... just read the documentation once more & I think I understand now !! I presumed the device on the monitor port should still be able to send traffic (ie Ping) but now I realise it's purely for receiving traffic but not for sending. I'll try again tomorrow & post back

thanks again

Irish Poetry - Karen O'Connor
Irish Poetry and Short Stories - Doghouse Books
Garten und Landschaftsbau