CHAPTER 1: INTRODUCTION1-30EMM-E6 User’s Guide1.10.6 Operation of the Subnet MaskThe Subnet Mask defines how your EMM-E6 treats SNMP Trap IPdestination addresses in its Trap table (see Chapter 7, Trap Table Screen,for additional information on traps).When using the Subnet Mask, the EMM-E6 logically determines one oftwo possible locations, either on or not on its own subnet, for each TrapIP destination address in its trap table. If the address is on its own subnet,the EMM-E6 transmits directly to the workstation with that address. If theaddress is not on its subnet, the EMM-E6 transmits to the workstationwith that address combined with the Default Gateway IP address. DefaultGateways are discussed later in this chapter.Modify the default Subnet Mask for the EMM-E6 when workstations inthe Trap table reside on a different subnet (i.e., across a gateway orexternal router), and you want these workstations to receive SNMP Trapsgenerated by the EMM-E6. Caution should be exercised whenconfiguring subnets, as a poorly subnetted network can greatly increasenetwork traffic by duplicating transmissions.1.10.7 Default GatewayThe Default Gateway is the IP address of the network or host to which allpackets addressed to unknown networks or hosts are sent. The DefaultGateway should be a perimeter or border device that connects the networkwith the rest of the world. The Default Gateway attempts to route thepacket to the correct destination. This gateway is often used by managersto handle all traffic between private networks and the Internet. If a DefaultGateway is not defined, the packets addressed to a network or hostaddress not found in the forwarding table will be dropped.
