Brocade Communications Systems Layer 3 Routing Configuration ICX 6650 - Manual (Page 86)

68 Brocade ICX 6650 Layer 3 Routing Configuration Guide
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Configuring IP parameters – Layer 3 Switches
In some environments, it may be necessary to reassign network addresses due to exhaustion of the
available address pool. In this case, the allocation mechanism reuses addresses with expired
leases.
Configuration notes for configuring DHCP servers
• DHCP server is supported in the Layer 2 and full Layer 3 software images.
• In the event of a controlled or forced switchover, a DHCP client will request from the DHCP
server the same IP address and lease assignment that it had before the switchover. After the
switchover, the DHCP Server feature will be automatically re-initialized on the new active
controller or management module.
• If any address from the configured DHCP pool is used, for example by the DHCP server, TFTP
server, etc., you must exclude the address from the network pool. For configuration
instructions, refer to
“Specifying addresses to exclude from the address pool” on page 76.
DHCP option 82 support
The DHCP relay agent information option (DHCP option 82) enables a DHCP relay agent to include
information about itself when forwarding client-originated DHCP packets to a DHCP server. The
DHCP server uses this information to implement IP address or other parameter-assignment
policies.
In a metropolitan Ethernet-access environment, the DHCP server can centrally manage IP address
assignments for a large number of subscribers. If DHCP option 82 is disabled, a DHCP policy can
only be applied per subnet, rather than per physical port. When DCHP option 82 is enabled, a
subscriber is identified by the physical port through which it connects to the network.
DHCP Server options
A Brocade ICX 6650 device configured as a DHCP server can support up to 1000 DHCP clients,
offering them the following options:
• NetBIOS over TCP/IP Name Server - Specifies a list of RFC1001/1002 NBNS name servers
listed in order of preference.
• Domain Name Server - Specifies a list of Domain Name System (RFC 1035) name servers
available to the client. Servers are listed in order of preference.
• Domain Name - Specifies the domain name the client should use when resolving hostnames
using the Domain Name system.
• Router Option - specifies a list of IP addresses for routers on the client subnet. Routers are
listed in order of preference.
• Subnet Mask - Specifies the client subnet mask (per RFC950).
• Vendor Specific Information - Allows clients and servers to exchange vendor-specific
information.
• Boot File - Specifies a boot image to be used by the client
• Next Bootstrap Server - Configures the IP address of the next server to be used for startup by
the client.
• TFTP Server - Configures the address or name of the TFTP server available to the client.