ECS4110-28P_Management Guide

C HAPTER 25 | General Security Measures
IPv4 Source Guard
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◆ Filtering rules are implemented as follows:
■
If DHCPv4 snooping is disabled (see page 916), 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 is static IP source guard binding, or
dynamic DHCP snooping binding, the packet will be forwarded.
■
If IP source guard if enabled on an interface for which IP source
bindings (dynamically learned via DHCP snooping or manually
configured) are not yet configured, the switch will drop all IP traffic
on that port, except for DHCP packets.
■
Only unicast addresses are accepted for static bindings.
EXAMPLE
This example enables IP source guard on port 5.
Console(config)#interface ethernet 1/5
Console(config-if)#ip source-guard sip
Console(config-if)#
RELATED COMMANDS
ip source-guard binding (936)
ip dhcp snooping (916)
ip dhcp snooping vlan (921)
ip source-guard
max-binding
This command sets the maximum number of entries that can be bound to
an interface. Use the no form to restore the default setting.
SYNTAX
ip source-guard [mode {acl | mac}] max-binding number
no ip source-guard [mode {acl | mac}] max-binding
mode - Specifies the learning mode.
acl - Searches for addresses in the ACL table.
mac - Searches for addresses in the MAC address table.
number - The maximum number of IP addresses that can be
mapped to an interface in the binding table. (Range: 1-5 for ACL
mode; 1-1024 for MAC mode)
DEFAULT SETTING
5