Enable Port Mirroring on Cisco

1 . Configure ports that should be monitored (Ports 0/15 to 0/17 with 0/19 are to be monitored) :

WS-C3560-24TS#conf t
WS-C3560-24TS(config)#monitor session 1 source interface FastEthernet0/15 - 17 , FastEthernet0/19 both
Note The above commands will monitor both inbound and outbound traffics for interfaces 15 to 17 with 19.

2 . Enable mirroring where the probe is connected to port 0/18 :

WS-C3560-24TS(config)#monitor session 1 destination interface FastEthernet 0/18

3 . If you assign port 18 as the monitoring port and configure the switch to monitor ports 15 – 17 and 19, show monitor displays the following :

WS-C3560-24TS#
sh monitor
Session 1
---------
Type : Local Session
Source Ports :
Both : Fa0/15-17,Fa0/19
Destination Ports : Fa0/18
Encapsulation : Native
Ingress : Disabled