Ochrona sieci lokalnych LAN

BST Laboratorium V

Port Security – CLI Commands

switchport mode access

Switch(config-if)#

•

Sets the interface mode as access

switchport port-security

Switch(config-if)#

•

Enables port security on the interface

switchport port-security maximum value

Switch(config-if)#

•

Sets the maximum number of secure MAC addresses for
the interface (optional)

Switchport Port-Security Parameters

Parameter

Description

mac-address mac-address

(Optional) Specify a secure MAC address for the port by entering a 48-bit MAC aaddress. You can add additional

secure MAC addresses up to the maximum value configured.

vlan vlan-id

(Optional) On a trunk port only, specify the VLAN ID and the MAC address. If no VLAN ID is specified, the native

VLAN is used.

vlan access

(Optional) On an access port only, specify the VLAN as an access VLAN.

vlan voice

(Optional) On an access port only, specify the VLAN as a voice VLAN

mac-address sticky

[mac-address]

(Optional) Enable the interface for sticky learning by entering only the mac-address sticky keywords. When sticky

learning is enabled, the interface adds all secure MAC addresses that are dynamically learned to the running

configuration and converts these addresses to sticky secure MAC addresses.

Specify a sticky secure MAC address by entering the mac-address sticky mac-address keywords..

maximum value

(Optional) Set the maximum number of secure MAC addresses for the interface. The maximum number of secure

MAC addresses that you can configure on a switch is set by the maximum number of available MAC

addresses allowed in the system. The active Switch Database Management (SDM) template determines this

number. This number represents the total of available MAC addresses, including those used for other Layer 2

functions and any other secure MAC addresses configured on interfaces.

The default setting is 1.

vlan [vlan-list]

(Optional) For trunk ports, you can set the maximum number of secure MAC addresses on a VLAN. If the vlan

keyword is not entered, the default value is used.

n

vlan: set a per-VLAN maximum value.

n

vlan vlan-list: set a per-VLAN maximum value on a range of VLANs separated by a hyphen or a series of

VLANs separated by commas. For nonspecified VLANs, the per-VLAN maximum value is used.

Port Security Violation Configuration

switchport port-security mac-address sticky

Switch(config-if)#



Enables sticky learning on the interface (optional)

switchport port-security violation {protect | restrict |
shutdown}

Switch(config-if)#



Sets the violation mode (optional)

switchport port-security mac-address mac-address

Switch(config-if)#



Enters a static secure MAC address for the interface
(optional)

Switchport Port-Security

Violation Parameters

Parameter

Description

protect

(Optional) Set the security violation protect mode. When the number of secure MAC
addresses reaches the limit allowed on the port, packets with unknown source
addresses are dropped until you remove a sufficient number of secure MAC addresses
or increase the number of maximum allowable addresses. You are not notified that a
security violation has occurred.

restrict

(Optional) Set the security violation restrict mode. When the number of secure MAC
addresses reaches the limit allowed on the port, packets with unknown source
addresses are dropped until you remove a sufficient number of secure MAC addresses
or increase the number of maximum allowable addresses. In this mode, you are notified
that a security violation has occurred.

shutdown

(Optional) Set the security violation shutdown mode. In this mode, a port security
violation causes the interface to immediately become error-disabled and turns off the
port LED. It also sends an SNMP trap, logs a syslog message, and increments the
violation counter. When a secure port is in the error-disabled state, you can bring it out
of this state by entering the errdisable recovery cause psecure-violation global
configuration command, or you can manually re-enable it by entering the shutdown and
no shut down interface configuration commands.

shutdown

vlan

Set the security violation mode to per-VLAN shutdown. In this mode, only the VLAN on
which the violation occurred is error-disabled.

Port Security Aging Configuration

switchport port-security aging {static | time time | type
{absolute | inactivity}}

Switch(config-if)#



Enables or disables static aging for the secure port or
sets the aging time or type



The aging command allows MAC-Addresses on the
Secure switchport to be deleted after the set aging time



This helps to avoid a situation where obsolete MAC-
Address occupy the table and saturates causing a
violation (when the max number exceeds)

Switchport Port-Security

Aging Parameters

Parameter

Description

static

Enable aging for statically configured secure
addresses on this port.

time time

Specify the aging time for this port. The range is 0 to
1440 minutes. If the time is 0, aging is disabled for
this port.

type absolute

Set absolute aging type. All the secure addresses
on this port age out exactly after the time (minutes)
specified and are removed from the secure address
list.

type inactivity

Set the inactivity aging type. The secure addresses
on this port age out only if there is no data traffic
from the secure source address for the specified
time period.

Typical Configuration

switchport mode access
switchport port-security
switchport port-security maximum 2
switchport port-security violation shutdown
switchport port-security mac-address sticky
switchport port-security aging time 120

Switch(config-if)#

S2

PC B

Verification – CLI Commands

sw-class#

show port-security

Secure Port MaxSecureAddr CurrentAddr SecurityViolation Security Action

(Count) (Count) (Count)

---------------------------------------------------------------------------

Fa0/12 2 0 0 Shutdown

---------------------------------------------------------------------------
Total Addresses in System (excluding one mac per port) : 0
Max Addresses limit in System (excluding one mac per port) : 1024

sw-class#

show port-security interface f0/12

Port Security : Enabled

Port status : Secure-down

Violation mode : Shutdown

Maximum MAC Addresses : 2

Total MAC Addresses : 1

Configured MAC Addresses : 0

Aging time : 120 mins

Aging type : Absolute

SecureStatic address aging : Disabled

Security Violation Count : 0

View Secure MAC Addresses

sw-class#

show port-security address

Secure Mac Address Table

-------------------------------------------------------------------

Vlan Mac Address Type Ports Remaining Age

(mins)

----

-----------

----

-----

-------------

1 0000.ffff.aaaa SecureConfigured Fa0/12 -

-------------------------------------------------------------------

Total Addresses in System (excluding one mac per port) : 0

Max Addresses limit in System (excluding one mac per port) : 1024

Configure Portfast

Command

Description

Switch(config-if)# spanning-tree

portfast

Enables PortFast on a Layer 2 access port and forces it to enter the

forwarding stateimmediately.

Switch(config-if)# no spanning-

tree portfast

Disables PortFast on a Layer 2 access port. PortFast is disabled by

default.

Switch(config)# spanning-tree

portfast default

Globally enables the PortFast feature on all nontrunking ports.

Switch# show running-config

interface type slot/port

Indicates whether PortFast has been configured on a port.

Server

Workstation

BPDU Guard

Switch(config)#

spanning-tree portfast bpduguard default



Globally enables BPDU guard on all ports with PortFast enabled

F

F

F

F

F

B

Root

Bridge

BPDU
Guard

Enabled

Attacker

STP

BPDU

Display the State of Spanning Tree

Switch# show spanning-tree summary totals
Root bridge for: none.
PortFast BPDU Guard is enabled
UplinkFast is disabled
BackboneFast is disabled
Spanning tree default pathcost method used is short
Name Blocking Listening Learning Forwarding STP Active
-------------------- -------- --------- -------- ---------- ----------

1 VLAN 0 0 0 1 1

<output omitted>

Root Guard

Switch(config-if)#

spanning-tree guard root



Enables root guard on a per-interface basis

Root Bridge

Priority = 0

MAC Address =

0000.0c45.1a5d

F

F

F

F

F

B

F

STP BPDU

Priority = 0

MAC Address = 0000.0c45.1234

Root

Guard

Enabled

Attacker

Verify Root Guard

Switch# show spanning-tree inconsistentports
Name Interface Inconsistency
-------------------- ---------------------- ------------------
VLAN0001 FastEthernet3/1 Port Type Inconsistent
VLAN0001 FastEthernet3/2 Port Type Inconsistent
VLAN1002 FastEthernet3/1 Port Type Inconsistent
VLAN1002 FastEthernet3/2 Port Type Inconsistent
VLAN1003 FastEthernet3/1 Port Type Inconsistent
VLAN1003 FastEthernet3/2 Port Type Inconsistent
VLAN1004 FastEthernet3/1 Port Type Inconsistent
VLAN1004 FastEthernet3/2 Port Type Inconsistent
VLAN1005 FastEthernet3/1 Port Type Inconsistent
VLAN1005 FastEthernet3/2 Port Type Inconsistent

Number of inconsistent ports (segments) in the system :10

Storm Control Configuration



Enables storm control



Specifies the level at which it is enabled



Specifies the action that should take place when the
threshold (level) is reached, in addition to filtering traffic

Switch(config-if)# storm-control broadcast level 75.5
Switch(config-if)# storm-control multicast level pps

2k

1k

Switch(config-if)# storm-control action shutdown

Storm Control Parameters

Parameter

Description

broadcast

This parameter enables broadcast storm control on the interface.

multicast

This parameter enables multicast storm control on the interface.

unicast

This parameter enables unicast storm control on the interface.

level level [level-low]

Rising and falling suppression levels as a percentage of total bandwidth of the port.

•

level: Rising suppression level. The range is 0.00 to 100.00. Block the flooding of storm
packets when the value specified for level is reached.

•

level-low: (Optional) Falling suppression level, up to two decimal places. This value must
be less than or equal to the rising suppression value.

level bps bps [bps-low]

Specify the rising and falling suppression levels as a rate in bits per second at which traffic is

received on the port.

•

bps: Rising suppression level. The range is 0.0 to 10000000000.0. Block the flooding of
storm packets when the value specified for bps is reached.

•

bps-low: (Optional) Falling suppression level, up to one decimal place. This value must be
equal to or less than the rising suppression value.

level pps pps [pps-low]

Specify the rising and falling suppression levels as a rate in packets per second at which traffic

is received on the port.

•

pps: Rising suppression level. The range is 0.0 to 10000000000.0. Block the flooding of
storm packets when the value specified for pps is reached.

•

pps-low: (Optional) Falling suppression level, up to one decimal place. This value must be
equal to or less than the rising suppression value.

action {shutdown|trap}

The action taken when a storm occurs on a port. The default action is to filter traffic and to not

send an SNMP trap.

The keywords have these meanings:

•

shutdown: Disables the port during a storm

•

trap: Sends an SNMP trap when a storm occurs

Verify Storm Control Settings

Switch# show storm-control

Interface

Filter State Upper Lower Current

---------

-------------

----------

---------

--------

-Gi0/1

Forwarding

20 pps

10 pps

5 pps

Gi0/2

Forwarding

50.00%

40.00%

0.00%

<output omitted>

switchport mode trunk

switchport trunk native vlan vlan_number

switchport nonegotiate

.

Switch(config-if)#



Specifies an interface as a trunk link

Switch(config-if)#



Prevents the generation of DTP frames.

Switch(config-if)#



Set the native VLAN on the trunk to an unused VLAN

Controlling Trunking

SPAN – CLI Commands

monitor session session_number source {interface
interface-id [, | -] [both | rx | tx]} | {vlan vlan-id [,
| -] [both | rx | tx]}| {remote vlan vlan-id}

monitor session session_number destination {interface
interface-id [, | -] [encapsulation replicate] [ingress
{dot1q vlan vlan-id | isl | untagged vlan vlan-id | vlan
vlan-id}]} | {remote vlan vlan-id}

Switch(config)#

Switch(config)#

Verify SPAN Configuration

Configuring RSPAN

2960-1

2960-2

2960-1(config)# vlan 100
2960-1(config-vlan)# remote-span
2960-1(config-vlan)# exit

2960-1(config)# monitor session 1 source interface FastEthernet 0/1
2960-1(config)# monitor session 1 destination remote vlan 100

reflector-port FastEthernet 0/24

2960-1(config)# interface FastEthernet 0/2
2960-1(config-if)# switchport mode trunk

2960-2(config)# monitor session 2 source remote vlan 100
2960-2(config)# monitor session 2 destination interface FastEthernet 0/3
2960-2(config)# interface FastEthernet 0/2
2960-2(config-if)# switchport mode trunk

1. Configure the RSPAN VLAN

2. Configure the RSPAN source ports and VLANs

3. Configure the RSPAN traffic to be forwarded

Verifying RSPAN Configuration

show monitor [session {session_number | all | local
| range list | remote} [detail]] [ | {begin | exclude
| include}expression]

2960-1

2960-2