Brocade Communications Systems Brocate Ethernet Access Switch 6910 User Manual
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Brocade 6910 Ethernet Access Switch Configuration Guide
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IP Source Guard
10
Command Usage
•
Source guard is used to filter traffic on an insecure port which receives messages from outside
the network or fire wall, 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 ip source guard command to disable this function on the
selected port.
•
When enabled, traffic is filtered based upon dynamic entries learned via DHCP snooping, 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, VLAN identifier, and port identifier.
•
Static addresses entered in the source guard binding table with the
command (
) are automatically configured with an infinite lease time. Dynamic entries
learned via DHCP snooping are configured by the DHCP server itself.
•
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 DHCP snooping is disabled (see
), 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 (225)
ip dhcp snooping (216)
ip dhcp snooping vlan (220)