Thinking about it further, there was probably nothing preventing my machine
from transmitting, but I probably was not connected to the network I was
configured for once the port was spanned.
---------------------- Forwarded by Kevin
Cullimore/FIRNY/NorthAmerica/MCKINSEY on 12/29/2000 09:42 PM
---------------------------
To: [EMAIL PROTECTED]
cc:
From: Kevin Cullimore/FIRNY/NorthAmerica/MCKINSEY
Date: 12/29/2000 09:40:22 PM
Subject: (Document link: Kevin Cullimore) Re: can SPAN port transmit?
My admittedly limited experience is as follows:
on the first day after a cutover to a set of 6500s and 6000s, I needed to
track down some server misconfigurations, so I asked that a server VLAN be
spanned to the port my laptop was using. Upon execution of those commands,
all normal functions of my workstation ceased (e-mail, browsing) but my
adapter was receiving traffic bound for the target VLAN. I asked the cisco
SE about this behavior, and he indicated that my experience was indicative
of how the span function works.
I did not try very hard to establish a workaround. It's probably worth some
more in-depth conversation about specific types of hardware and software,
to see if we are merely talking past each other.
Priscilla Oppenheimer <[EMAIL PROTECTED]>@groupstudy.com on 12/29/2000
05:42:28 PM
Please respond to Priscilla Oppenheimer <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED]
To: [EMAIL PROTECTED], [EMAIL PROTECTED]
cc:
Subject: Re: can SPAN port transmit?
The reason I ask is that my client is developing a network management box
that will connect to a SPAN port and collect traffic as well as
occasionally send SNMP queries and other UDP packets.
He realizes that if the user were collecting data from many ports there
would be performance issues. However, he wants to know, in the absence of
performance problems, will his device be able to send some queries? Is
sending disabled on the SPAN port? The other answers (from people who have
tried it) make me think the answer is no, sending is not disabled.
Priscilla
At 04:46 PM 12/29/00, [EMAIL PROTECTED] wrote:
>Cisco employees have confirmed for me that devices connected to span ports
>are unable to act as normal hosts by design.
>
>
>
>
>
>
>Priscilla Oppenheimer <[EMAIL PROTECTED]>@groupstudy.com on 12/29/2000
>03:27:52 PM
>
>Please respond to Priscilla Oppenheimer <[EMAIL PROTECTED]>
>
>Sent by: [EMAIL PROTECTED]
>
>To: [EMAIL PROTECTED]
>cc: (bcc: Kevin Cullimore)
>Subject: can SPAN port transmit?
>
>
>Hi folks,
>
>If I connect a Sniffer-like device to the SPAN port of a switch, will the
>Sniffer-like device be able to transmit data?
>
>My guess is no. From my reading on Cisco's SwitchProbe external hardware
>probes, it appears that the SwitchProbe needs an additional port to send
>data to a network management system. One port connects to a SPAN port on
>the switch and the other port connects to a normal port and is configured
>in "management mode."
>
>But, does anyone have experience with trying to send from a device
>connected to a SPAN port?
>
>Thanks
>
>Priscilla
________________________
Priscilla Oppenheimer
http://www.priscilla.com
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