Cisco port security mac address limit

Port security aging Disabled. Aging time is 0. Static aging is disabled. Type is absolute. Port Security Configuration Guidelines Port security can only be configured on static access ports or trunk ports. A secure port cannot belong to a Gigabit EtherChannel port group.

Overview of Port Security

Note Voice VLAN is only supported on access ports and not on trunk ports, even though the configuration is allowed. When you enable port security on an interface that is also configured with a voice VLAN, set the maximum allowed secure addresses on the port to two. If you connect more than one PC to the Cisco IP phone, you must configure enough secure addresses to allow one for each PC and one for the phone.

When a trunk port configured with port security and assigned to an access VLAN for data traffic and to a voice VLAN for voice traffic, entering the switchport voice and switchport priority extend interface configuration commands has no effect. When you enter a maximum secure address value for an interface, and the new value is greater than the previous value, the new value overwrites the previously configured value. If the new value is less than the previous value and the number of configured secure addresses on the interface exceeds the new value, the command is rejected.

The switch does not support port security aging of sticky secure MAC addresses. This table summarizes port security compatibility with other port-based features.

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  • Interface - Configuring Port Security [Cisco Catalyst Series Switches] - Cisco Systems;
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How to Configure Port Security. In this mode, the VLAN is error disabled instead of the entire port when a violation occurs. Related Concepts Port Security. Enabling and Configuring Port Security Aging Use this feature to remove and add devices on a secure port without manually deleting the existing secure MAC addresses and to still limit the number of secure addresses on a port. Related Concepts Port Security Aging. Monitoring Port Security This table displays port security information. Configuration Examples for Port Security This example shows how to enable port security on a port and to set the maximum number of secure addresses to Port security.

Configure Switch Port Security MAC Address Sticky - Part 2

Disabled on a port. Sticky address learning.

Maximum number of secure MAC addresses per port. Violation mode. Port security aging. Trunk port. Routed port. SPAN source port. SPAN destination port.


Tunneling port. Protected port. IEEE Voice VLAN port 6. IP source guard. Flex Links. Switch configure terminal. Enters global configuration mode. Switch config-if switchport mode access. Switch config-if switchport voice vlan Enables voice VLAN on a port. Switch config-if switchport port-security. Enable port security on the interface. Switch config-if switchport port-security maximum Optional vlan —sets a per-VLAN maximum value Enter one of these options after you enter the vlan keyword: Switch config-if switchport port-security violation restrict.

That means that an attacker could connect to your network through a wall socket and potentially threaten your network. If you know which devices will be connected to which ports, you can use the Cisco security feature called port security. By using port security, a network administrator can associate specific MAC addresses with the interface, which can prevent an attacker to connect his device.

This way you can restrict access to an interface so that only the authorized devices can use it. If an unathorized device is connected, you can decide what action the switch will take, for example discarding the traffic and shutting down the port. All three options discards the traffic from the unauthorized device.

The restrict and shutdown options send a log messsages when a violation occurs. Certainly port-security isn't the end all be all I was faced same problem.

Cisco CCNA – Port Security and Configuration

I solved this by setting age to 1 minute. I think with these 4 things installed you have secure enough environment without paying for One important "gotcha" to remember when configuring port security, no matter how you configure it, you still need the "switchport port-security" command with no parameters to enable it. For instance, I see this all the time:.

So many times I've been told that port security was configured, only to find that it wasn't enabled with the generic version of the command. If you want to use HSRP with port-security and keep to the default of one MAC address per switchport you can use the following command on the routers:. Thanks for the article.

We use it as hexem mentioned - as protection against MAC flood attacks. In fact, that's what the Cisco chaps were advising at Networkers this year for the reasons covered above. Here is our edge port port-security config:. Be aware that sticky mac addresses do not expire, hence the errdisable ports cannot auto recover if sticky mac addresses are enabled.

I have configured one port in a x series with the following commands and the Voip phone was showing " configuring IP address".

Cisco CCNA – Port Security and Configuration –

Also remember that if you are using sticky, you need to make sure your WRITE your config after all addresses are learned. Otherwise, if the switch loses power, all ports will dynamically relearn new mac's when it comes up. Interesting paper about port security: Hi, grrreat site. I'm going for CCNP switch and found this on the site which i'm following for a long time. Welcome, Guest! Port Security By stretch Monday, May 3, at 4: Enabling Port Security Port security can be enabled with default parameters by issuing a single command on an interface: We can view the default port security configuration with show port-security: Enabled Port Status: Secure-down Violation Mode: Shutdown Aging Time: Absolute SecureStatic Address Aging: When a host connects to the switch port, the port learns the host's MAC address as the first frame is received: Secure-up Violation Mode: Observe what happens as soon as the second host attempts to send traffic: Security violation occurred, caused by MAC address Secure-shutdown Violation Mode: Tweaking Port Security Violation Mode Port security can be configured to take one of three actions upon detecting a violation: By changing the violation mode to restrict , we are still alerted when a violation occurs, but legitimate traffic remains unaffected: Restrict Aging Time: This can be modified, for example, to accommodate both a host and an IP phone connected in series on a switch port: Switch config-if switchport port-security maximum 1 vlan access Switch config-if switchport port-security maximum 1 vlan voice MAC Address Learning An administrator has the option of statically configuring allowed MAC addresses per interface.

Switch config-if switchport port-security mac-address b. Current configuration: Switch config-if no switchport port-security mac-address b. The following example configures expiration of MAC addresses after five minutes of inactivity: Inactivity SecureStatic Address Aging: