1. A method for keeping track of various hardware devices, such as printers, connected to a network. SNMP can tell network administrators when printers are low on paper or toner, or when a paper jam has occurred. SNMP seems destined to be replaced by die Microsoft at Work standard or the Desktop Management Interface (DMI) standard. From QUECID

2. A set of standards for communication with devices connected to a TCP/IP network. Examples of these devices include routers, hubs, and switches.

3. The Internet infrastructure is composed of lots of hardware scattered around the place. SNMP is the method that allows someone to "manage" all that equipment. By the word "manage" I mean do things like monitor the amount of traffic flowing through the equipment, trigger when faults occur, change the configuration of equipment remotely, and so forth. Key point: Most equipment comes with default passwords (aka. community strings) of public and private. These allow you to read information from the device (traffic, temperature, voltage, etc.) and re-configure it. Key point: A common technique is to traceroute to a victim's dial-up machine thereby discovering the IP address of the hardware they've dialed into. Then, you can send SNMP commands with the "private" community strings telling the hardware to hang-up on the victim. Also, spammers have used this technique to find the true login name of the user. From Hacking-Lexicon