DHCP CLI Commands
15-8 Configuring DHCP XSR User’s Guide
DHCP CLI Commands
The XSR offers CLI commands to provide the following functionality:
• DHCP Server address pool(s) with related parameters and DHCP options/vendor extensions.
You can configure a DHCP address pool with a name that is a symbolic string (e.g.,
Accounting) with ip dhcp pool. Configuring a DHCP address pool also places you in DHCP
pool mode - (config-dhcp-pool)# - from which you can configure pool parameters. The
XSR supports adding 1000 network addresses per pool and one DHCP pool per network.
• Create manual bindings of IP addresses and client hardware addresses - Manual bindings are
comprised of a:
–host - the DHCP client’s IP address and subnet mask or prefix length, entered with host
–hardware-addre ss - the DHCP client’s MAC address and platform protocol, entered with
hardware-address, or
–client-identifier - the DHCP client’s unique marker is its combined media type and MAC
address, entered with client-identifier.
• Delete client bindings from the DHCP Server. Clear ip dhcp binding removes an automatic
address binding from the DHCP database; no host, no hardware-address or no client-
id remove manual bindings depending on which command was entered first when the
binding was created.
• DHCP Server boot file(s) - The boot file is used to store a boot image for the client. The boot
image is often the operating system a client uses to load. It is configured with bootfile.
• Enable BOOTP Relay by configuring a destination address for UDP broadcasts with ip
helper-address.
• Set domain name and DNS server - To put a client in the general group of networks
comprising the domain, use domain-name. To specify the DNS server clients query when they
need to correlate host names to IP addresses, use dns-server.
• Specify the NetBIOS server and node type for Microsoft clients - DHCP clients query DNS
servers when they must resolve host names to IP addresses; enter an IP address of the
NetBIOS MS WINS server using netbios-name-server. The XSR supports four node types of
DHCP clients: broadcast, peer-to-peer, mixed, and hybrid. They can be specified using
netbios-node-type.
• Configure a default router for the client - After a DHCP client has booted, the client begins
sending packets to its default router. The IP address of the default router is required and
should be on the same subnet as the client. Set using default-router.
• Configure the address lease time - IP addresses assigned by a DHCP Server have a one-day
lease - the interval during which the address is valid. Specify with lease.
• Set the number of ping packets and ping wait interval - the DHCP Server pings an IP address
twice before assigning a particular address to a requesting client. If the ping is unanswered,
the server assumes (with a high probability) that the address is not in use and assigns the
address to the requesting client. Use ip dhcp ping packets to change the number of ping
packets the server should send to the IP address before assigning the address.
•Use ip dhcp ping timeout to specify the period the server must wait before timing out a
ping request.
• Monitor and maintain DHCP Server services by issuing the following show commands. Show
ip dhcp bindings displays bindings data on the DHCP Server including lease expiration
dates. Show ip dhcp conflict displays address conflicts found by a DHCP Server when