NETGEAR UTM5-100NAS, UTM50-100NAS manual V1.0, January

ProSecure Unified Threat Management (UTM) Appliance Reference Manual

Whether or not DHCP is enabled, how the PCs accesses the server’s LAN address impacts the inbound rules. For example:

•If your external IP address is assigned dynamically by your ISP (DHCP enabled), the IP address might change periodically as the DHCP lease expires. Consider using Dyamic DNS so that external users can always find your network (see “Configuring Dynamic DNS” on page 3-19).

•If the IP address of the local server PC is assigned by DHCP, it might change when the PC is rebooted. To avoid this, use the Reserved (DHCP Client) feature in the LAN Groups menu to keep the PC’s IP address constant (see “Setting Up Address Reservation” on page 4-17).

•Local PCs must access the local server using the PCs’ local LAN address. Attempts by local PCs to access the server using the external WAN IP address will fail.

Note: See “Configuring Port Triggering” on page 5-46 for yet another way to allow certain types of inbound traffic that would otherwise be blocked by the firewall.

Note: The UTM always blocks denial of service (DoS) attacks. A DoS attack does not attempt to steal data or damage your PCs, but overloads your Internet connection so you cannot use it (that is, the service becomes unavailable). For example, multiple concurrent connections of the same application from one host or IP addresses (such as multiple DNS queries from one PC) triggers the UTM’s DoS protection. For more information about protecting the UTM from incoming threats, see “Using the Intrusion Prevention System” on page 5-49.

Table 5-3 on page 5-8describes the fields that define the rules for inbound traffic and that are common to most Inbound Service screens (see Figure 5-4 on page 5-15, Figure 5-7 on page 5-18and Figure 5-10 on page 5-21).

The steps to configure inbound rules are described in the following sections:

•“Setting LAN WAN Rules” on page 5-12

•“Setting DMZ WAN Rules” on page 5-15

•“Setting LAN DMZ Rules” on page 5-19

Firewall Protection 5-7

v1.0, January 2010