Cisco IOS capture lazy dog

# create a buffer
monitor capture buffer buffer1 size 512 max-size 512 circular

# create a capture point
monitor capture point ip cef capture1 FastEthernet 0/1/3 both

# associate capture with the buffer 'buffer1'
monitor capture point associate capture1 buffer1

# Start monitor the capture
monitor capture point start capture1

# Show the buffer
show monitor capture buffer buffer1 dump

# Stop the capture
monitor capture point stop capture1