Configure Multicast Pass-Through, 158

ProSecure Unified Threat Management (UTM) Appliance

Table 30. Attack Checks screen settings (continued)

Setting

Description

LAN Security Checks

Block UDP flood	Select the Block UDP flood check box to prevent the UTM from accepting more
	than 20 simultaneous, active User Datagram Protocol (UDP) connections from a
	single device on the LAN. By default, the Block UDP flood check box is cleared.
	A UDP flood is a form of denial of service attack that can be initiated when one
	device sends many UDP packets to random ports on a remote host. As a result, the
	distant host does the following:
	1. Checks for the application listening at that port.
	2. Sees that no application is listening at that port.
	3. Replies with an ICMP Destination Unreachable packet.
	When the victimized system is flooded, it is forced to send many ICMP packets,
	eventually making it unreachable by other clients. The attacker might also spoof the
	IP address of the UDP packets, ensuring that the excessive ICMP return packets do
	not reach the attacker, thus making the attacker’s network location anonymous.

Disable Ping Reply	Select the Disable Ping Reply on LAN Ports check box to prevent the UTM from
on LAN Ports	responding to a ping on a LAN port. A ping can be used as a diagnostic tool. Keep
	this check box cleared unless you have a specific reason to prevent the UTM from
	responding to a ping on a LAN port.

VPN Pass through

IPSec

PPTP L2TP

When the UTM functions in NAT mode, all packets going to the remote VPN gateway are first filtered through NAT and then encrypted according to the VPN policy. For example, if a VPN client or gateway on the LAN side of the UTM wants to connect to another VPN endpoint on the WAN side (placing the UTM between two VPN endpoints), encrypted packets are sent to the UTM. Because the UTM filters the encrypted packets through NAT, the packets become invalid unless you enable the VPN Pass through feature.

To enable the VPN tunnel to pass the VPN traffic without any filtering, select any or all of the following check boxes:

•IPSec. Disables NAT filtering for IPSec tunnels.

•PPTP. Disables NAT filtering for PPTP tunnels.

•L2TP. Disables NAT filtering for L2TP tunnels. By default, all three check boxes are selected.

3.Click Apply to save your settings.