Users Guide

OS10(config)# ip domain-list vrf-vrfblue dns3
OS10(config)# ip domain-list vrf vrf-blue dns4
OS10(config)# ip domain-list vrf vrf-blue 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.
aaa authentication system:local
ip domain-name dell.com
ip domain-list f10.com
ip name-server 1.1.1.1 2::2
ip host dell-f10.com 10.10.10.10
snmp-server community public read-only
snmp-server contact http://www.dell.com/support/
snmp-server location United States
debug radius false
DHCP snooping
DHCP snooping is a layer 2 security feature that helps networking devices to monitor DHCP messages and block untrusted or rouge DHCP
servers.
When you enable DHCP snooping on a switch, it begins to monitor transactions between trusted DHCP servers and DHCP clients and use
the information to build the DHCP snooping binding table. You congure interfaces that connect to DHCP servers as trusted ports. All
other ports are untrusted by default.
The DHCP snooping binding table contains the following information:
• Host IP addresses
• Host MAC addresses
• Interfaces facing the hosts
• Client VLANs
• Lease time
• DHCP binding type – static or dynamic
The switch interprets DHCP servers that are connected to trusted ports on the switch as legitimate servers. When a switch receives DHCP
server-initiated packets (UDP destination port 67) on an untrusted interface, it drops the packet.
When a switch receives DHCP renew, release, or decline messages from a host, it checks the DHCP snooping binding table for a match. If
the information in the DHCP message matches the table, the switch forwards the message to the DHCP server. If the information does not
match, the switch interprets the host as an unauthorized host and drops the packet.
The DHCP snooping switch removes a dynamically-learned DHCP snooping binding entry when one of the following occurs:
• Lease expiry
• DHCP release event from the client
• DHCP decline event from the client
• User actions, such as DHCP clear or disabling DHCP snooping
You can add a static DHCP snooping binding entry using the CLI. If you add a static entry for a host, any dynamic entry that is present for
the same host is overwritten. The switch does not remove static entries if it receives DHCP RELASE or DHCP DECLINE packets.
By default, DHCP snooping is disabled globally and enabled on VLANs. For the DHCP snooping feature to work, enable it globally.
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System management