D-Link DSA-3200 Información técnica descargar pdf (Pagina 147)

xStack

DGS-3200 Series Layer 2 Managed Gigabit Ethernet Switch Web UI Reference Guide

133

DHCP Snooping Option

If DHCP snooping is enabled, the switch learns IP-MAC pairs by snooping DHCP packets automatically and then saving them to

the IP-MAC-Port Binding white list. This enables a hassle-free configuration because the administrator does not need to manually

enter each IMPB entry. A prerequisite for this is that the valid DHCP server’s IP-MAC pair must be on the switch’s IMPB list;

otherwise the DHCP server packets will be dropped. DHCP snooping is generally considered to be more secure because it

enforces all clients to acquire IP through the DHCP server.

An example of DHCP snooping in which PC-A and PC-B get their IP addresses from a DHCP server is depicted below. The

switch snoops the DHCP conversation between PC-A, PC-B, and the DHCP server. The IP address, MAC address, and connecting

ports of both PC-A and PC-B are learned and stored in the switch’s IMPB white list. Therefore, these PCs will be able to connect

to the network. Then there is PC-C, whose IP address is manually configured by the user. Since this PC’s IP-MAC pair does not

match the one on Switch’s IMPB white list, traffic from PC-C will be blocked.

192.168.1.1 00E0-0211-111 Port 1

192.168.1.2 00E0-0211-222 Port 2

Figure 6 - 5. Example of DHCP Snooping

The IP-MAC-Port Binding (IMPB) folder contains five windows: IMPB Global Settings, IMPB Port Settings, IMPB Entry

Settings, DHCP Snooping Entries, and MAC Blocked List.

IMPB Global Settings

Users can enable or disable the global IMPB settings: Trap Log State and DHCP Snoop state, on the Switch.

The Trap/Log field will enable and disable the sending of trap log messages for IP-MAC binding. When enabled, the Switch will

send a trap message to the SNMP agent and the Switch log when an ARP packet is received that doesn’t match the IP-MAC

binding configuration set on the Switch.

The DHCP Snoop State field will enable and disable the DHCP Snooping option.

To view the following window, click Security > IP-MAC-Port Binding (IMPB) > IMPB Global Settings:

Figure 6 - 6. IMPB Global Settings window

IMP Binding Enabled

Address Learning

White List

(IP assigned by DHCP for

PC-A and PC-B)

192.168.1.2

00E0-0211-2222

192.168.1.1

00E0-0211-3333

(IP manually configured by user)

DHCP Server

PC-B

PC-C

PC-A

Doesn’t match the

White List block PC-C

192.168.1.1

00E0-0211-1111

1 2 ... 142 143 144 145 146 147 148 149 150 151 152 ... 320 321

Comentarios a estos manuales

Sin comentarios

D-Link DSA-3200 Información técnica Pagina 147

Comentarios a estos manuales

Relacionado con productos y manuales para Redes D-Link DSA-3200