According to Cisco documentation:
Finally there is a feature that was missing from IOS in the past. This is the ability to easily capture packets travelling through the router, and export the captured data to PCAP format so that you can view it with third party tools (like Wireshark). The packets can also be viewed locally on the router. The configuration example below shows how to enable packet capture (supported in IOS version 12.4(20)T):
Cisco-Router# monitor capture buffer mycapturedata size 128 max-size 128 circular
Cisco-Router# monitor capture point ip cef capturepoint1fastEthernet 1/1 both
Cisco-Router# monitor cap point associate capturepoint1 mycapturedata
However, I am running IOS 12.4(24)T1 but I can not enable it:
Enter configuration commands, one per line. End with CNTL/Z.
event-trace Tracing of system events
session Configure a SPAN session
IOS version is c2800nm-adventerprisek9-mz.124-24.T1.bin
Anyone know why? Thanks.