Chapter 23 IP Source Guard
MGS-3712/MGS-3012F User’s Guide
188
23.1.2.1 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 (
• 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.
23.1.2.2 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.
23.1.2.3 Syslog
The Switch can send syslog messages to the specified syslog server (
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.
23.1.2.4 Configuring ARP Inspection
Follow these steps to configure ARP inspection on the Switch.
1
Configure DHCP snooping. See
"
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 MGS-3712
Page 2: ......
Page 7: ...Safety Warnings MGS 3712 MGS 3012F User s Guide 7 ...
Page 8: ...Safety Warnings MGS 3712 MGS 3012F User s Guide 8 ...
Page 20: ...Table of Contents MGS 3712 MGS 3012F User s Guide 20 ...
Page 28: ...List of Tables MGS 3712 MGS 3012F User s Guide 28 ...
Page 30: ...30 ...
Page 38: ...Chapter 2 Hardware Installation and Connection MGS 3712 MGS 3012F User s Guide 38 ...
Page 50: ...50 ...
Page 70: ...Chapter 6 System Status and Port Statistics MGS 3712 MGS 3012F User s Guide 70 ...
Page 82: ...Chapter 7 Basic Setting MGS 3712 MGS 3012F User s Guide 82 ...
Page 84: ...84 ...
Page 132: ...Chapter 15 Link Aggregation MGS 3712 MGS 3012F User s Guide 132 ...
Page 142: ...Chapter 17 Port Security MGS 3712 MGS 3012F User s Guide 142 ...
Page 148: ...Chapter 18 Classifier MGS 3712 MGS 3012F User s Guide 148 Figure 80 Classifier Example ...
Page 153: ...Chapter 19 Policy Rule MGS 3712 MGS 3012F User s Guide 153 Figure 83 Policy Example ...
Page 154: ...Chapter 19 Policy Rule MGS 3712 MGS 3012F User s Guide 154 ...
Page 170: ...Chapter 21 Multicast MGS 3712 MGS 3012F User s Guide 170 ...
Page 184: ...Chapter 22 Authentication Accounting MGS 3712 MGS 3012F User s Guide 184 ...
Page 214: ...Chapter 25 Two Rate Three Color Marker MGS 3712 MGS 3012F User s Guide 214 ...
Page 215: ...215 PART IV IP Application Static Route 217 DHCP 221 ...
Page 216: ...216 ...
Page 220: ...Chapter 26 Static Route MGS 3712 MGS 3012F User s Guide 220 ...
Page 228: ...Chapter 27 DHCP MGS 3712 MGS 3012F User s Guide 228 ...
Page 230: ...230 ...
Page 256: ...Chapter 30 Diagnostic MGS 3712 MGS 3012F User s Guide 256 ...
Page 260: ...Chapter 31 Syslog MGS 3712 MGS 3012F User s Guide 260 ...
Page 274: ...274 ...
Page 278: ...Chapter 36 Troubleshooting MGS 3712 MGS 3012F User s Guide 278 ...
Page 286: ...286 ...
Page 290: ...Appendix A Common Services MGS 3712 MGS 3012F User s Guide 290 ...
Page 294: ...Appendix B Legal Information MGS 3712 MGS 3012F User s Guide 294 ...