Specifications

Niagara Release 2.3
Revised: May 22, 2002 Niagara Networking & Connectivity Guide
Chapter 3 Connecting on a LAN
Using DHCP
3–26
Step 5 Reconnect with the Admin Tool using the IP address assigned by the DHCP server.
The DHCP administrator can tell you this address, or you can figure it out (see
“Determining Network Settings”).
Step 6 Verify that the network configuration parameters (DNS servers, etc.) have been
properly assigned.
Trouble-
shooting DHCP
Problems on the
JACE-4/5
This section discusses common DHCP problem scenarios on the JACE-4/5 and
approaches to resolving them.
Lease Renewal Failure
Per the DHCP specification, the JACE will periodically renew its lease, even when
using a reserved address. The DHCP server defines the length of the renewal period.
If the renewal request ever fails (for example, if the DHCP server is offline, or the
Ethernet cable is disconnected when the renewal request occurs) and the lease
expires, then, per the DHCP specification, the JACE disables its network interface.
The DHCP specification was written that way to prevent a host from using an IP
address for which it no longer has a valid lease.
When a JACE has failed to renew its lease, it cannot be accessed using the Ethernet
connection and the heartbeat LED blinks rapidly. To fix this problem, correct the
problem that caused the renewal to fail, and reboot the JACE.
DHCP Reservation not Working
If the DHCP administrator has set up the reserved address, but the JACE fails to pick
it up on the initial boot after you enabled DHCP, then you may have given the DHCP
administrator the wrong MAC address. Verify the MAC address of the JACE using
the previous procedure, or with the
ifShow command (see “Using Target Shell
Commands”).
However, if the JACE receives the reserved IP address, but upon renewal of its
DHCP lease gets assigned another IP address, then the fault may lie with the DHCP
reservation. If the DHCP server is Windows-based, the reservation must be made on
both the primary DHCP server and any backup DHCP servers that handle the same
DHCP scope. A DHCP scope is a range of IP addresses that the server can assign. If
the scope can be assigned from multiple servers, then each server must also have
reservations listed for the scope. To determine which DHCP server handled the last
DHCP request for the JACE, see the
dhcpcParamsShow command.