Chapter 2
Catalyst 2960 Switch Cisco IOS Commands
ip address
Use the ip address interface configuration command to set an IP address for the Layer 2 switch. Use the
no form of this command to remove an IP address or to disable IP processing.
Syntax Description
ip-address
subnet-mask
secondary
Defaults
No IP address is defined.
Command Modes
Interface configuration
Command History
Release
12.2(25)FX
Usage Guidelines
If you remove the switch IP address through a Telnet session, your connection to the switch will be lost.
Hosts can find subnet masks using the Internet Control Message Protocol (ICMP) Mask Request
message. Routers respond to this request with an ICMP Mask Reply message.
You can disable IP processing on a particular interface by removing its IP address with the no ip address
command. If the switch detects another host using one of its IP addresses, it will send an error message
to the console.
You can use the optional keyword secondary to specify an unlimited number of secondary addresses.
Secondary addresses are treated like primary addresses, except the system never generates datagrams
other than routing updates with secondary source addresses. IP broadcasts and ARP requests are handled
properly, as are interface routes in the IP routing table.
Note
If any router on a network segment uses a secondary address, all other devices on that same segment
must also use a secondary address from the same network or subnet. Inconsistent use of secondary
addresses on a network segment can very quickly cause routing loops.
If your switch receives its IP address from a Bootstrap Protocol (BOOTP) or a DHCP server and you
remove the switch IP address by using the no ip address command, IP processing is disabled, and the
BOOTP or the DHCP server cannot reassign the address.
78-16882-01
ip address ip-address subnet-mask [secondary]
no ip address [ip-address subnet-mask] [secondary]
IP address.
Mask for the associated IP subnet.
(Optional) Specifies that the configured address is a secondary IP address. If
this keyword is omitted, the configured address is the primary IP address.
Modification
This command was introduced.
Catalyst 2960 Switch Command Reference
ip address
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