Reference Guide

This option secures all DHCP trac that goes through a DHCP relay agent, and ensures that communication between the DHCP relay
agent and the DHCP server is not compromised.
The DHCP relay agent inserts Option 82 before forwarding DHCP packets to the DHCP server. The DHCP server includes Option 82 back
in its response to the relay agent. The relay agent uses this information to forward a reply out the interface on which the request was
received rather than ooding it on the entire VLAN. However, the relay agent removes Option 82 from its DHCP responses before
forwarding the responses to the client.
NOTE: Option 82 is supported, but not congurable.
View DHCP Information
Use the show ip dhcp binding command to view the DHCP binding table entries.
View DHCP Binding Table
OS10# show ip dhcp binding
IP Address Hardware address Lease expiration Hostname
+--------------------------------------------------------------------------
11.1.1.254 00:00:12:12:12:12 Jan 27 2016 06:23:45
Total Number of Entries in the Table = 1
System domain name and list
If you enter a partial domain, the system searches dierent domains to nish or fully qualify that partial domain. A fully qualied domain
name (FQDN) is any name that terminates with a period or dot.
OS10 searches the host table rst to resolve the partial domain. The host table contains both statically congured and dynamically learned
host and IP addresses. If OS10 cannot resolve the domain, it tries the domain name assigned to the local system. If that does not resolve
the partial domain, the system searches the list of domains congured.
You can congure the ip domain-list command up to ve times to enter a list of possible domain names. The system searches the
domain names in the order they were congured until a match is found or the list is exhausted.
1 Enter a domain name in CONFIGURATION mode (up to 64 alphanumeric characters).
ip domain-name name
2 Add names to complete unqualied host names in CONFIGURATION mode.
ip domain-list name
Congure local system domain name and list
OS10(config)# ip domain-name ntengg.com
OS10(config)# ip domain-list dns1
OS10(config)# ip domain-list dns2
OS10(config)# ip domain-list dns3
OS10(config)# ip domain-list dns4
OS10(config)# ip domain-list dns5
View local system domain name information
OS10# show running-configuration
! Version 10.2.9999E
! Last configuration change at Feb 20 04:50:33 2017
!
username admin password $6$q9QBeYjZ$jfxzVqGhkxX3smxJSH9DDz7/3OJc6m5wjF8nnLD7/VKx8SloIhp4NoGZs0I/
UNwh8WVuxwfd9q4pWIgNs5BKH.
System management
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