Chapter 24 IP Source Guard
GS-2750 User’s Guide
198
24.1.2.1 ARP Inspection and MAC Address Filters
When the Switch identifies an unauthorized ARP packet, it automatically creates a MAC
address filter to block traffic from the source MAC address and source VLAN ID of the
unauthorized ARP packet. You can configure how long the MAC address filter remains in the
Switch.
These MAC address filters are different than regular MAC address filters (
Chapter 10 on page
103
).
• They are stored only in volatile memory.
• They do not use the same space in memory that regular MAC address filters use.
• They appear only in the
ARP Inspection
screens and commands, not in the
MAC
Address Filter
screens and commands.
24.1.2.2 Trusted vs. Untrusted Ports
Every port is either a trusted port or an untrusted port for ARP inspection. This setting is
independent of the trusted/untrusted setting for DHCP snooping. You can also specify the
maximum rate at which the Switch receives ARP packets on untrusted ports.
The Switch does not discard ARP packets on trusted ports for any reason.
The Switch discards ARP packets on untrusted ports in the following situations:
• The sender’s information in the ARP packet does not match any of the current bindings.
• The rate at which ARP packets arrive is too high.
24.1.2.3 Syslog
The Switch can send syslog messages to the specified syslog server (
Chapter 34 on page 281
)
when it forwards or discards ARP packets. The Switch can consolidate log messages and send
log messages in batches to make this mechanism more efficient.
24.1.2.4 Configuring ARP Inspection
Follow these steps to configure ARP inspection on the Switch.
1
Configure DHCP snooping. See
Section 24.1.1.4 on page 197
.
"
It is recommended you enable DHCP snooping at least one day before you
enable ARP inspection so that the Switch has enough time to build the binding
table.
2
Enable ARP inspection on each VLAN.
3
Configure trusted and untrusted ports, and specify the maximum number of ARP packets
that each port can receive per second.
Summary of Contents for GS-2750
Page 2: ......
Page 7: ...Safety Warnings GS 2750 User s Guide 7 This product is recyclable Dispose of it properly ...
Page 8: ...Safety Warnings GS 2750 User s Guide 8 ...
Page 26: ...List of Figures GS 2750 User s Guide 26 ...
Page 32: ...32 ...
Page 40: ...Chapter 2 Hardware Installation and Connection GS 2750 User s Guide 40 ...
Page 48: ...48 ...
Page 58: ...Chapter 4 The Web Configurator GS 2750 User s Guide 58 ...
Page 64: ...Chapter 5 Initial Setup Example GS 2750 User s Guide 64 ...
Page 70: ...Chapter 6 System Status and Port Statistics GS 2750 User s Guide 70 ...
Page 82: ...Chapter 7 Basic Setting GS 2750 User s Guide 82 ...
Page 84: ...84 ...
Page 120: ...Chapter 11 Spanning Tree Protocol GS 2750 User s Guide 120 ...
Page 134: ...Chapter 15 Link Aggregation GS 2750 User s Guide 134 ...
Page 144: ...Chapter 17 Port Security GS 2750 User s Guide 144 ...
Page 155: ...Chapter 19 Policy Rule GS 2750 User s Guide 155 Figure 73 Policy Example example ...
Page 156: ...Chapter 19 Policy Rule GS 2750 User s Guide 156 ...
Page 160: ...Chapter 20 Queuing Method GS 2750 User s Guide 160 ...
Page 166: ...Chapter 21 VLAN Stacking GS 2750 User s Guide 166 ...
Page 194: ...Chapter 23 Authentication Accounting GS 2750 User s Guide 194 ...
Page 220: ...220 ...
Page 232: ...Chapter 28 Differentiated Services GS 2750 User s Guide 232 ...
Page 242: ...Chapter 29 DHCP GS 2750 User s Guide 242 ...
Page 252: ...Chapter 30 VRRP GS 2750 User s Guide 252 ...
Page 254: ...254 ...
Page 278: ...Chapter 32 Access Control GS 2750 User s Guide 278 ...
Page 280: ...Chapter 33 Diagnostic GS 2750 User s Guide 280 ...
Page 284: ...Chapter 34 Syslog GS 2750 User s Guide 284 ...
Page 298: ...Chapter 39 Routing Table GS 2750 User s Guide 298 ...
Page 301: ...301 PART VI Product Specifications Product Specifications 303 ...
Page 302: ...302 ...
Page 310: ...310 ...
Page 322: ...Appendix B Legal Information GS 2750 User s Guide 322 ...
Page 328: ...Appendix C Customer Support GS 2750 User s Guide 328 ...