Dell FCX624-S Laptop User Manual


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842 PowerConnect B-Series FCX Configuration Guide
53-1002266-01
Configuring IP parameters – Layer 3 Switches
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For DHCP client hitless support in an IronStack, the stack mac command must be used to
configure the IronStack MAC address, so that the MAC address does not change in the event of
a switchover or failover. If stack mac is not configured, the MAC address/IP address pair
assigned to a DHCP client will not match after a switchover or failover. Furthermore, in the
Layer 3 router image, if the stack mac configuration is changed or removed and the
management port has a dynamic IP address, when a DHCP client tries to renew its lease from
the DHCP server, the DHCP server will assign a different IP address.
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 “Specify addresses to exclude from the address pool” on page 850.
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 PowerConnect 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 of the TFTP server available to the client.
A DHCP server assigns and manages IPv4 addresses from multiple address pools, using dynamic
address allocation. The DHCP server also contains the relay agent to forward DHCP broadcast
messages to network segments that do not support these types of messages.