Verifying That A Trusted Dhcp Server Is Working Correctly - Juniper JUNOS OS 10.3 - SOFTWARE Manual

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Verifying That a Trusted DHCP Server Is Working Correctly

Purpose
Action
Meaning
Copyright © 2010, Juniper Networks, Inc.
IP address and lease time—that is, the time, in seconds, remaining before the lease
expires. Static IP addresses have no assigned lease time. The statically configured entry
never expires.
If the DHCP server had been configured as untrusted, no entries would be added to the
DHCP snooping database and nothing would be shown in the output of the
command.
snooping binding
Enabling DHCP Snooping (CLI Procedure) on page 2910
Enabling DHCP Snooping (J-Web Procedure) on page 2911
Configuring Static IP Addresses for DHCP Bindings on Access Ports (CLI Procedure)
on page 2925
Example: Configuring Port Security, with DHCP Snooping, DAI, MAC Limiting, and MAC
Move Limiting, on an EX Series Switch on page 2849
Example: Configuring DHCP Snooping, DAI , and MAC Limiting on an EX Series Switch
with Access to a DHCP Server Through a Second Switch on page 2873
Example: Configuring DHCP Snooping and DAI to Protect the Switch from ARP Spoofing
Attacks on page 2866
Monitoring Port Security on page 2933
Troubleshooting Port Security on page 2945
Verify that a DHCP trusted server is working on the switch. See what happens when the
DHCP server is trusted and then untrusted.
Send some DHCP requests from network devices (here they are DHCP clients) connected
to the switch.
Display the DHCP snooping information when the interface on which the DHCP server
connects to the switch is trusted. The following output results when requests are sent
from the MAC addresses and the server has provided the IP addresses and leases:
user@switch> show dhcp snooping binding
DHCP Snooping Information:
MAC Address IP Address
----------------- ----------
00:05:85:3A:82:77 192.0.2.17
00:05:85:3A:82:79 192.0.2.18
00:05:85:3A:82:80 192.0.2.19
00:05:85:3A:82:81 192.0.2.20
00:05:85:3A:82:83 192.0.2.21
00:05:85:27:32:88 192.0.2.22
When the interface on which the DHCP server connects to the switch has been set to
trusted, the output (see preceding sample) shows, for each MAC address, the assigned
Chapter 96: Verifying Port Security
Lease Type VLAN
----- ---- ----
600 dynamic employee—vlan
653 dynamic employee—vlan
720 dynamic employee—vlan
932 dynamic employee—vlan
1230 dynamic employee—vlan
3200 dynamic employee—vlan
show dhcp
Interface
---------
ge-0/0/1.0
ge-0/0/1.0
ge-0/0/2.0
ge-0/0/2.0
ge-0/0/2.0
ge-0/0/2.0
2935