CLI Reference Guide-R07

Chapter 27 | IP Interface Commands
IPv4 Interface
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Command Usage
◆ An IP address must be assigned to this device to gain management access over
the network or to connect the router to existing IP subnets. A specific IP address
can be manually configured, or the router can be directed to obtain an address
from a BOOTP or DHCP server. Valid IP addresses consist of four numbers, 0 to
255, separated by periods. Anything other than this format is not be accepted
by the configuration program.
◆ An interface can have only one primary IP address, but can have many
secondary IP addresses. In other words, secondary addresses need to be
specified if more than one IP subnet can be accessed through this interface.
Note that a secondary address cannot be configured prior to setting the
primary IP address, and the primary address cannot be removed if a secondary
address is still present. Also, if any router/switch in a network segment uses a
secondary address, all other routers/switches in that segment must also use a
secondary address from the same network or subnet address space.
◆ If bootp or dhcp options are selected, the system will immediately start
broadcasting service requests for all VLANs configured to obtain address
assignments through BOOTP or DHCP. IP is enabled but will not function until a
BOOTP or DHCP reply has been received. Requests are broadcast periodically
by the router in an effort to learn its IP address. (BOOTP and DHCP values can
include the IP address, default gateway, and subnet mask). If the DHCP/BOOTP
server is slow to respond, you may need to use the ip dhcp restart client
command to re-start broadcasting service requests, or reboot the switch.
Note: Each VLAN group can be assigned its own IP interface address. You can
manage the switch via any of these IP addresses.
Example
In the following example, the device is assigned an address in VLAN 1.
Console(config)#interface vlan 1
Console(config-if)#ip address 192.168.1.5 255.255.255.0
Console(config-if)#
This example assigns an IP address to VLAN 2 using a classless network mask.
Console(config)#interface vlan 2
Console(config-if)#ip address 10.2.2.1/24
Console(config-if)#
Related Commands
ip dhcp restart client (602)
ip default-gateway (650)
ipv6 address (661)