C
LIENT
S
ECURITY
7-16
• Blocking NetBIOS traffic commonly used for resource sharing in a
peer-to-peer environment to ensure that no privileged client data is
passed to other data ports.
Command Attributes
•DHCP Request – Blocks DHCP request packets. (Default: Disabled)
- In cases where the IP address for a client attached to a downlink port
is fixed (i.e., at the VDSL port on the CPE), you should use this
command to block any DHCP requests from the client.
- To specify a port list, use a hyphen to indicate a range of ports, or a
comma to indicate a group of non-consecutive ports.
- This switch provides a total of 7 masks for filtering functions,
including IP-MAC address packet filtering, NetBIOS packet filtering,
DHCP packet filtering, and ACLs. One mask is allocated to DHCP
packet filtering if enabled on any interface. This mask will be released
for use by other filtering functions if DHCP packet filtering is
disabled on all interfaces.
•DHCP Reply – Blocks DHCP reply packets. (Default: Disabled)
- In cases where the client address is dynamically assigned by the service
provider, but you need to ensure that the DHCP service reply is only
obtained through an authorized uplink port, you can use this
command to block DHCP replies from all unauthorized ports
(commonly specifying all data ports).
- To specify a port list, use a hyphen to indicate a range of ports, or a
comma to indicate a group of non-consecutive ports.
- This switch provides a total of 7 masks for filtering functions,
including IP-MAC address packet filtering, NetBIOS packet filtering,
DHCP packet filtering, and ACLs. One mask is allocated to DHCP
packet filtering if enabled on any interface. This mask will be released
for use by other filtering functions if DHCP packet filtering is
disabled on all interfaces.