Users Guide

you congure IP source address validation on a member port of a virtual local area network (VLAN) and then attempt to apply an
access list to the VLAN, Dell Networking OS displays the rst line in the following message. If you rst apply an ACL to a VLAN
and then attempt enable IP source address validation on one of its member ports, Dell Networking OS displays the second line in
the following message.
% Error: Vlan member has access-list configured.
% Error: Vlan has an access-list configured.
NOTE: If you enable DHCP Snooping globally and you have any congured L2 ports, any IP ACL, MAC ACL, or DHCP
source address validation ACL does not block DHCP packets.
• Dell Networking OS provides 40K entries that can be divided between leased addresses and excluded addresses. By extension,
the maximum number of pools you can congure depends on the subnet mask that you give to each pool. For example, if all
pools were congured for a /24 mask, the total would be 40000/253 (approximately 158). If the subnet is increased, more pools
can be congured. The maximum subnet that can be congured for a single pool is /17. Dell Networking OS displays an error
message for congurations that exceed the allocated memory.
• This platform supports 4000 DHCP Snooping entries.
• All platforms support Dynamic ARP Inspection on 16 VLANs per system. For more information, refer to Dynamic ARP Inspection.
NOTE: If the DHCP server is on the top of rack (ToR) and the VLTi (ICL) is down due to a failed link, when a VLT node
is rebooted in BMP (Bare Metal Provisioning) mode, it is not able to reach the DHCP server, resulting in BMP failure.
Congure the System to be a DHCP Server
A DHCP server is a network device that has been programmed to provide network conguration parameters to clients upon request.
Servers typically serve many clients, making host management much more organized and ecient.
The following table lists the key responsibilities of DHCP servers.
Table 20. DHCP Server Responsibilities
DHCP Server Responsibility Description
Address Storage and Management DHCP servers are the owners of the addresses used by DHCP
clients.The server stores the addresses and manages their use,
keeping track of which addresses have been allocated and which
are still available.
Conguration Parameter Storage and Management DHCP servers also store and maintain other parameters that are
sent to clients when requested. These parameters specify in
detail how a client is to operate.
Lease Management DHCP servers use leases to allocate addresses to clients for a
limited time. The DHCP server maintains information about each
of the leases, including lease length.
Responding To Client Requests DHCP servers respond to dierent types of requests from
clients, primarily, granting, renewing, and terminating leases.
Providing Administration Services DHCP servers include functionality that allows an administrator
to implement policies that govern how DHCP performs its other
tasks.
Conguring the Server for Automatic Address Allocation
Automatic address allocation is an address assignment method by which the DHCP server leases an IP address to a client from a
pool of available addresses.
An address pool is a range of IP addresses that the DHCP server may assign. The subnet number indexes the address pools.
To create an address pool, follow these steps.
1. Access the DHCP server CLI context.
CONFIGURATION mode
Dynamic Host Conguration Protocol (DHCP)
285