Cisco Catalyst 2950 User Manual

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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 28 Configuring Network Security with ACLs
Examples for Compiling ACLs
This example uses an extended ACL to deny traffic from port 80 (HTTP). It permits all other types of
traffic.
Switch(config)# access-list 106 deny tcp any any eq 80
Switch(config)# access-list 106 permit ip any any
Switch(config)# interface gigabitethernet0/2
Switch(config-if)# ip access-group 106 in
Numbered ACL Examples
This example shows that the switch accepts addresses on network 36.0.0.0 subnets and denies all packets
coming from 56.0.0.0 subnets. The ACL is then applied to packets entering an interface.
Switch(config)# access-list 2 permit 36.0.0.0 0.255.255.255
Switch(config)# access-list 2 deny 56.0.0.0 0.255.255.255
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# ip access-group 2 in
Extended ACL Examples
In this example of using an extended ACL, you have a network connected to the Internet, and you want
any host on the network to be able to form TCP Telnet and SMTP connections to any host on the Internet.
Switch(config)# access-list 102 permit tcp any 128.88.0.0 0.0.255.255 eq 23
Switch(config)# access-list 102 permit tcp any 128.88.0.0 0.0.255.255 eq 25
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# ip access-group 102 in
SMTP uses TCP port 25 on one end of the connection and a random port number on the other end. The
same port numbers are used throughout the life of the connection. Mail packets coming in from the
Internet have a destination port of 25. Because the secure system behind the switch always accepts mail
connections on port 25, the incoming services are controlled.
Named ACL Example
The Marketing_group ACL allows any TCP Telnet traffic to the destination address and wildcard
171.69.0.0 0.0.255.255 and denies any other TCP traffic. It permits any other IP traffic.
Switch(config)# ip access-list extended marketing_group
Switch(config-ext-nacl)# permit tcp any 171.69.0.0 0.0.255.255 eq telnet
Switch(config-ext-nacl)# deny tcp any any
Switch(config-ext-nacl)# permit ip any any
The ACLs are applied to permit a port with the Marketing_group ACL applied to incoming traffic.
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# ip access-group marketing_group in
...

Cisco Catalyst 2950 Specifications

General

Forwarding Bandwidth	8.8 Gbps
Switching Capacity	13.6 Gbps
Forwarding Rate	6.6 Mpps
Weight	3.6 kg
RAM	16 MB
Flash Memory	8 MB
Operating Humidity	10% to 85% non-condensing
Uplink Ports	2 x 10/100/1000Base-T
Dimensions	4.4 cm x 44.5 cm x 24.2 cm
Remote Management Protocol	SNMP, Telnet, HTTP
Features	Quality of Service (QoS), VLAN support
Compliant Standards	IEEE 802.3, IEEE 802.3u, IEEE 802.1D, IEEE 802.1Q, IEEE 802.1p
Status Indicators	system
Operating Temperature	0 to 45°C
Ports	24 x 10/100 Ethernet ports
MAC Address Table Size	8, 192 entries
Power Supply	Internal 100-240V AC, 50-60Hz