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Simple Network Management Protocol (SNMP)
User's Guide
Version 4.19

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Chapters

- SNMP Introduction
  - Top of chapter
  - Scope and Purpose
  - Prerequisites
  - Definitions
  - About This Manual
  - Where to Find More Information
- Agent Functional Description
  - Top of chapter
  - Features
  - SNMPv1, SNMPv2 and SNMPv3
  - Operation
  - Sub-agents and MIB Loading
  - Contexts and Communities
  - Management of the Agent
  - Notifications
  - Discovery
- Manager Functional Description
  - Top of chapter
  - Features
  - Operation
  - MIB loading
- The MIB Compiler
  - Top of chapter
  - Operation
  - Importing MIBs
  - MIB Consistency Checking
  - .hrl File Generation
  - Emacs Integration
  - Compiling from a Shell or a Makefile
  - Deviations from the Standard
- Running the application
  - Top of chapter
  - Configuring the application
  - Modifying the Configuration Files
  - Starting the application
  - Debugging the application
- Definition of Agent Configuration Files
  - Top of chapter
  - Agent Information
  - Contexts
  - System Information
  - Communities
  - MIB Views for VACM
  - Security data for USM
  - Notify Definitions
  - Target Address Definitions
  - Target Parameters Definitions
- Definition of Manager Configuration Files
  - Top of chapter
  - Manager Information
  - Users
  - Agents
  - Security data for USM
- Agent Implementation Example
  - Top of chapter
  - MIB
  - Default Implementation
  - Manual Implementation
- Manager Implementation Example
  - Top of chapter
  - The example manager
  - A simple standard test
- Instrumentation Functions
  - Top of chapter
  - Instrumentation Functions
  - Using the ExtraArgument
  - Default Instrumentation
  - Atomic Set
- Definition of Instrumentation Functions
  - Top of chapter
  - Variable Instrumentation
  - Table Instrumentation
- Definition of Agent Net if
  - Top of chapter
  - Mandatory Functions
  - Messages
- Definition of Manager Net if
  - Top of chapter
  - Mandatory Functions
  - Messages
- Audit Trail Log
  - Top of chapter
  - Agent Logging
  - Manager Logging
- Advanced Agent Topics
  - Top of chapter
  - When to use a Sub-agent
  - Agent Semantics
  - Sub-agents and Dependencies
  - Distributed Tables
  - Fault Tolerance
  - Using Mnesia Tables as SNMP Tables
  - Deviations from the Standard
- SNMP Appendix A
  - Top of chapter
  - Appendix A
- SNMP Appendix B
  - Top of chapter
  - Appendix B

# 14 Audit Trail Log

The chapter Audit Trail Log describes the audit trail logging.

Both the agent and the manager can be configured to log incoming and outgoing messages. It uses the Erlang standard log mechanism disk_log for logging. The size and location of the log files are configurable. A wrap log is used, which means that when the log has grown to a maximum size, it starts from the beginning of the log, overwriting existing log records.

The log can be either a read, write or a read_write.

### 14.1 Agent Logging

For the agent, a write, means that all set requests and their responses are stored. No get requests or traps are stored in a write. A read_write, all requests, responses and traps are stored.

The log uses a raw data format (basically the BER encoded message), in order to minimize the CPU load needed for the log mechanism. This means that the log is not human readable, but needs to be formatted off-line before it can be read. Use the function snmpa:log_to_txt for this purpose.

### 14.2 Manager Logging

For the manager, a write, means that all requests (set and get) and their responses are stored. No traps are stored in a write. A read_write, all requests, responses and traps are stored.

The log uses a raw data format (basically the BER encoded message), in order to minimize the CPU load needed for the log mechanism. This means that the log is not human readable, but needs to be formatted off-line before it can be read. Use the function snmpm:log_to_txt for this purpose.