Chapter 6 - Switch Configuration
Switches typically have no power button
System LED = indicates success/failure of POST
 Off = switch is off
 Green = operating normally
 Amber = has power but not operating properly
RPS (redundant power supply) LED
 Off = RPS off or not installed
 Solid green = RPS connected and operational
 Blinking green = RPS providing power to another switch in stack
 Solid amber = RPS, connected but not operational
 Blinking amber = switch is operating on RPS
Port Mode LED = three states
 STAT = status
 UTL = utilization
 FDUP = full duplex
Port LED = one per port, based on current port mode LED
STAT LED on
 off = no link
 Solid green = link operational;
 Blinking green = send/receive data
 Alternating green/amber = link forward
 Solid amber = port is not forwarding
FDUP LED on
 Green = full-duplex
 Off = half-duplex
Default configuration
Hostname is Switch
No passwords set
Each port (interface) is referenced by slot and port number (0/1)
Defaults to auto mode = automatically detect half-or full-duplex
Defaults to VLAN 1 = default management VLAN, one broadcast domain
There is no VLAN database (vlan.dat) in flash
CDP, STP (Spanning tree protocol) enabled
No IP address assigned
show run
displays running configurations
show interface
displays port (interface) properties
show interface vlan1 displays IP address
show vlan
displays defined VLAN
show flash
display contents of flash directory
show version
display IOS version, configuration register settings, IOS filename,
switch model and serial number, amount of memory, number ports
show ip interface vlan1
Switch>
Switch#
enable
config t
displays switch IP properties
User EXEC mode
enable or privileged mode
enters privileged mode
enter configuration mode
Reset switch to defaults
delete flash:vlan.dat
erase startup-config
reload
Deletes vlan.dat from flash
Erases startup configuration
Reloads the switch
Uses same router commands to set hostname, console and telnet passwords
type commands manually or use system configuration dialog
hostname name
line con 0
Line console configuration
password pwd
login
line vty 0 4
Telnet configuration, lines 0 - 4
password pwd
login
Assign Switch IP address, default gateway
Needed to allow telnet access to switch
int VLAN1
no shut
ip address address subnet
ip default-gateway address
Provide web-based interface e to switch config
Must have ip address and default gateway configured
ip http server
Turns on http service
ip http port num
set port for web service, default is 80
Configure ports
defaults to auto-speed and auto-duplex
can manually set
int slot/port
duplex full
or half or auto
speed 100
or 10 or 1000
Configuring MAC addresses
MAC address table used to forward between ports
Supports dynamic, permanent and static addresses
Defaults to dynamic
Switching tables map source addresses to an incoming port
Each entry time stamped at the time it is stored and each time it is referenced in the table
Addresses not referenced within set amount time (default = 300 secs) are removed from the table
Multiple MAC addresses can be mapped to a particular port
show mac-address-table
clear mac-address-table
displays switching table contents
erases dynamic switching table contents
Statically assign MAC address to a port
Entry does not age out
Enhances security
mac-address-table static mac-address vlan vlan-id slot/port
Configure port security
Limit number of MAC addresses per port
First dynamically learned address = secured address
2950 series:
int fa0/4
switchport mode access
switchport port-security
enables port security
switchport port-security mac-address sticky
dynamically captures secure MAC address
switchport port-security maximum 1
sets max number of MAC addresses (default)
switchport port-security violation shutdown
sets action if violation occurs (default)
2900 series:
int fa0/4
port security
port security max-mac-count 1
port security action shutdown
enables port security
sets max number of MAC address (default is 132)
set action if violation occurs (default is snmp trap)
Other port security:
Unused ports can be shutdown
int fa0/4
shutdown
View port security
show port-security
show port-security int slot/port
show port-security address
Actions to take when adding, moving, changing MAC address
Add:
Configure port security
Configure MAC address
Change:
Remove MAC address security restrictions
Move:
Add address to new port
Configure port security on new port
Configure MAC address on new port
Remove old port configuration
Password Recovery
Hold down MODE button during switch startup, release after STAT LED no longer lit