NETGEAR GS748T User Manual

74
GS748T Smart Switch
Services — DHCP Filtering
DHCP Filtering is a useful feature that can be employed as a security measure against
unauthorized DHCP servers. A known attack is when an unauthorized DHCP server
responds to a client that is requesting an IP address. The server configures the gateway for
the client to be equal to the IP address of the server. At that point, the client sends all of its IP
traffic destined to other networks to the unauthorized machine. This gives the attacker the
possibility of snooping traffic for passwords or employing a man-in-the-middle attack. DHCP
Filtering works by allowing the administrator to configure each port as either a trusted port or
an untrusted port. The port that has the authorized DHCP server should be configured as a
trusted port. Any DHCP responses received on a trusted port are forwarded. All other ports
should be configured as untrusted. Any DHCP (or BootP) responses received are discarded.
From the Services link, you can access the following pages:
• DHCP Filtering Configuration on page 75
• Interface Configuration on page 75
Location Information
Civic Displays the physical location, such as the street address, the remote device
has advertised in the location TLV. For example, 123 45th St. E. The field
value length range is 6–160 characters.
Coordinates Displays the location map coordinates the remote device has advertised in
the location TLV, including latitude, longitude and altitude.
ECS ELIN Displays the Emergency Call Service (ECS) Emergency Location
Identification Number (ELIN) the remote device has advertised in the location
TLV. The field range is 10–25.
Unknown Displays unknown location information for the remote device.
Network Policies
Application Type Specifies the media application type associated with the policy advertised by
the remote device.
VLAN ID Specifies the VLAN ID associated with the policy.
VLAN Type Specifies whether the VLAN associated with the policy is tagged or untagged.
User Priority Specifies the priority associated with the policy.
DSCP Specifies the DSCP associated with a particular policy type.
LLDP Unknown TLVs
Type Displays the unknown TLV type field.
Value Displays the unknown TLV value field.
Field Description

NETGEAR GS748T Specifications

General

Basic switching RJ-45 Ethernet ports quantity	48
MAC address table	16000 entries
Packet buffer memory	1.632 MB
Maximum data transfer rate	1 Gbit/s
Latency	20 µs
I/O ports	48 RJ-45 connectors for 10BASE-T, 100BASE-TX, and 1000BASE-T (Auto Uplink on all ports) 4 SFP slots for fiber Gigabit Ethernet modules
Dimensions (WxDxH)	440 x 260 x 43 mm
Power requirements	100-240VAC 50/60 Hz
Networking features	10BASE-T, 100BASE-TX, 1000BASE-T
Connectivity technology	Wired
Full duplex	Yes
Networking standards	IEEE 802.3x
Minimum system requirements	Category 5 network cables Network card for each PC Network software (e.g., Windows)
Mean time between failures (MTBF)	69930 h
Safety	UL listed (UL 1950)/cUL, IEC950/EN60950
LED indicators	Link, Power
Power consumption (typical)	70 W
Storage temperature (T-T)	-10 - 70 °C
Operating temperature (T-T)	0 - 40 °C
Operating relative humidity (H-H)	10 - 90 %

Weight and Dimensions

Weight	4000 g