3Com Switch 7750 Configuration Guide Guide

576 CHAPTER 54: DHCP SERVER CONFIGURATION
[SW7750] dhcp server ip-pool 2
[SW7750-dhcp-pool-2] network 10.1.1.128 mask 255.255.255.128
[SW7750-dhcp-pool-2] domain-name aabbcc.com
[SW7750-dhcp-pool-2] dns-list 10.1.1.2
[SW7750-dhcp-pool-2] expired day 5
[SW7750-dhcp-pool-2] nbns-list 10.1.1.4
[SW7750-dhcp-pool-2] gateway-list 10.1.1.254
Troubleshooting a
DHCP Server
Symptom
The IP address dynamically assigned by a DHCP server to a client conflicts with the
IP address of another host.
Analysis
With DHCP enabled, IP address conflicts are usually caused by IP addresses that are
manually configured on hosts.
Solution
■ Disconnect the DHCP client from the network and then check whether there is
a host using the conflicting IP address by performing ping operation on
another host on the network, with the conflicting IP address as the destination
and an enough timeout time.
■ The IP address is manually configured on a host if you receive a response
packet of the ping operation. You can then disable the IP address from being
dynamically assigned by using the dhcp server forbidden-ip command on the
DHCP server.
■ Attach the DHCP client to the network, release the dynamically assigned IP
address and obtain an IP address again. For example, enter DOS by executing
the cmd command in Windows XP, and then release the IP address by
executing the ipconfig/release command. Then obtain an IP address again by
executing the ipconfig/renew command.