Allied Telesis Rapier i Series - Manual (Page 2)

Page 2 | AlliedWare™ OS How To Note: DHCP Snooping on Rapier-style switches
Introduction
This document contains the following contents:
Introduction .............................................................................................................................................. 1
Which products and software version does this information apply to? .............................. 2
Related How To Notes ................................................................................................................... 3
DHCP snooping ....................................................................................................................................... 3
Minimum configuration ................................................................................................................... 3
The database ..................................................................................................................................... 4
Trusted and non-trusted ports ..................................................................................................... 6
Enabling DHCP snooping ............................................................................................................... 6
Static binding ..................................................................................................................................... 6
Completely removing the DHCP snooping database .............................................................. 7
DHCP Option 82 .................................................................................................................................... 8
Protocol details ................................................................................................................................. 9
Configuring Option 82 .................................................................................................................. 10
DHCP filtering ........................................................................................................................................ 11
Configuring filtering ....................................................................................................................... 11
ARP security .................................................................................................................................... 12
Resource considerations .............................................................................................................. 12
Configuration examples ....................................................................................................................... 14
Configuring the switch for DHCP snooping, filtering and Option 82, when it is
acting as a layer 2 switch ....................................................................................................... 14
Configuring the switch for DHCP snooping, filtering, and Option 82, when it is
acting as a layer 3 BOOTP Relay Agent ............................................................................ 17
Troubleshooting ..................................................................................................................................... 20
No trusted ports configured ....................................................................................................... 20
The DHCP client continually sends requests instead of a discover ................................... 21
Switch is dropping ARPs ............................................................................................................... 22
Displaying log entries .................................................................................................................... 24
Appendix 1: ISC DHCP server .......................................................................................................... 25
Which products and software version does this
information apply to?
The information provided in this document applies to the following switches, running
AlliedWare version 2.7.6 and above:
z AT-8800 series
z AT-8600 series
z AT-8700XL series
z Rapier and Rapier i series