SMC Networks SMC8150L2 manual Syntax Ip source-guard sip sip-macno ip source-guard, Disabled

4 Command Line Interface

Syntax

ip source-guard {sip sip-mac}no ip source-guard

•sip - Filters traffic based on IP addresses stored in the binding table.

•sip-mac- Filters traffic based on IP addresses and corresponding MAC addresses stored in the binding table.

Default Setting

Disabled

Command Mode

Interface Configuration (Ethernet)

Command Usage

•Source guard is used to filter traffic on an unsecure port which receives messages from outside the network or firewall, and therefore may be subject to traffic attacks caused by a host trying to use the IP address of a neighbor.

•Setting source guard mode to “sip” or “sip-mac” enables this function on the selected port. Use the “sip” option to check the VLAN ID, source IP address, and port number against all entries in the binding table. Use the “sip-mac” option to check these same parameters, plus the source MAC address. Use the no source guard command to disable this function on the selected port.

•When enabled, traffic is filtered based upon dynamic entries learned via DHCP snooping, static entries configured in the DHCP snooping table, or static addresses configured in the source guard binding table.

•Table entries include a MAC address, IP address, lease time, entry type (Static-IP-SG-Binding, Dynamic-DHCP-Binding, Static-DHCP-Binding), VLAN identifier, and port identifier.

•Static addresses entered in the source guard binding table with the ip source-guard binding command (page 4-229)are automatically configured with an infinite lease time. Dynamic entries learned via DHCP snooping are configured by the DHCP server itself; static entries include a manually configured lease time.

•If the IP source guard is enabled, an inbound packet’s IP address (sip option) or both its IP address and corresponding MAC address (sip-mac option) will be checked against the binding table. If no matching entry is found, the packet will be dropped.

•Filtering rules are implemented as follows:

-If the DHCP snooping is disabled (see page 4-231),IP source guard will check the VLAN ID, source IP address, port number, and source MAC address (for the sip-mac option). If a matching entry is found in the binding table and the entry type is static IP source guard binding, the packet will be forwarded.

-If the DHCP snooping is enabled, IP source guard will check the VLAN ID, source IP address, port number, and source MAC address (for the sip-mac option). If a matching entry is found in the binding table and the entry type

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