Cisco Catalyst 3750-X User Manual

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 42 Configuring IP Unicast Routing
Configuring IP Addressing
Assigning IP Addresses to Network Interfaces
An IP address identifies a location to which IP packets can be sent. Some IP addresses are reserved for
special uses and cannot be used for host, subnet, or network addresses. RFC 1166, “Internet Numbers,”
contains the official description of IP addresses.
An interface can have one primary IP address. A mask id
entifies the bits that denote the network number
in an IP address. When you use the mask to subnet a network, the mask is referred to as a subnet mask.
To receive an assigned network number, contact your Internet service provider.
Beginning in privileged EXEC mode, follow these steps t
o assign an IP address and a network mask to
a Layer 3 interface:
Use of Subnet Zero
Subnetting with a subnet address of zero is strongly discouraged because of the problems that can arise
if a network and a subnet have the same addresses. For example, if network 131.108.0.0 is subnetted as
255.255.255.0, subnet zero would be written as 131.108.0.0, which is the same as the network address.
IRDP Disabled.
Defaults when enabled:
• Broadcast IRDP advertisements.
• Maximum interval between advertisements: 600 seconds.
• Minimum interval between advertisements: 0.75 times max interval
• Preference: 0.
IP proxy ARP Enabled.
IP routing Disabled.
IP subnet-zero Disabled.
Table 42-1 Default Addressing Configuration (continued)
Feature Default Setting
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
interface interface-id Enter interface configuration mode, and specify the Layer 3
interface to configure.
Step 3
no switchport Remove the interface from Layer 2 configuration mode (if it is a
physical interface).
Step 4
ip address ip-address subnet-mask Configure the IP address and IP subnet mask.
Step 5
no shutdown Enable the interface.
Step 6
end Return to privileged EXEC mode.
Step 7
show interfaces [interface-id]
show ip interface [in
terface-id]
show running-config interface [int
erface-id]
Verify your entries.
Step 8
copy running-config startup-config (Optional) Save your entries in the configuration file.

Cisco Catalyst 3750-X Specifications

General

Brand	Cisco
Model	Catalyst 3750-X
Category	Switch
Language	English