1-7
Security Overview
Network Security Features
Access Control 
Lists (ACLs)
none ACLs can filter traffic to or from a host, a group of hosts, 
or entire subnets. Layer 3 IP filtering with Access Control 
Lists (ACLs) enables you to improve network 
performance and restrict network use by creating 
policies for:
• Switch Management Access: Permits or denies in-
band management access. This includes preventing 
the use of certain TCP or UDP applications (such as 
Telnet, SSH, WebAgent, and SNMP) for transactions 
between specific source and destination IP 
addresses.)
• Application Access Security: Eliminating unwanted 
IP, TCP, or UDP traffic by filtering packets where they 
enter or leave the switch on specific interfaces.
Note on ACL Security Use:
ACLs can enhance network security by blocking 
selected IP traffic, and can serve as one aspect of 
maintaining network security. However, because ACLs 
do not provide user or device authentication, or 
protection from malicious manipulation of data carried 
in IP packet transmissions, they should not be relied 
upon for a complete security solution. 
Chapter 10, “IPv4 Access 
Control Lists (ACLs)”
Port Security, 
MAC Lockdown, 
and MAC 
Lockout
none The features listed below provide device-based access 
security in the following ways:
• Port security: Enables configuration of each switch 
port with a unique list of the MAC addresses of 
devices that are authorized to access the network 
through that port. This enables individual ports to 
detect, prevent, and log attempts by unauthorized 
devices to communicate through the switch. Some 
switch models also include eavesdrop prevention in 
the port security feature. 
• MAC lockdown: This “static addressing” feature is 
used as an alternative to port security to prevent 
station movement and MAC address “hijacking” by 
allowing a given MAC address to use only one 
assigned port on the switch. MAC lockdown also 
restricts the client device to a specific VLAN.
• MAC lockout: This feature enables blocking of a 
specific MAC address so that the switch drops all 
traffic to or from the specified address.
Chapter 14, “Configuring and 
Monitoring Port Security”
See also “Precedence of 
Port-Based Security 
Options” on page 1-15
Feature Default 
Setting
Security Guidelines More Information and 
Configuration Details