Apache HTTP Error Log
Server errors, warnings, and diagnostic messages
Apache HTTP Server error log entries recording server errors, warnings, configuration issues, client errors, SSL problems, module failures, and script execution errors
Overview
Records error conditions, warnings, configuration issues, and diagnostic information from the Apache HTTP Server. Includes server startup/shutdown events, client connection errors, script failures, SSL/TLS issues, module loading problems, and other operational events.
When Generated:
- Server startup, shutdown, or restart events
- Configuration syntax errors or warnings
- Client request errors (invalid headers, malformed requests)
- Backend script failures (PHP, Python, CGI timeouts or errors)
- SSL/TLS handshake failures or certificate issues
- Module loading failures or dependency errors
- File not found errors (404s for non-logged access requests)
- Resource limit or timeout conditions
Security Relevance:
HighCompliance:
Frequency Notes:
Medium-frequency events during business hours (40 events/hour) with some activity during nights (24 events/hour) due to automated processes and maintenance tasks. Weekends see reduced activity (16 events/hour). Error rates vary significantly based on server health, application stability, and configuration quality.
Resources
Documentation
- Apache HTTP Server Documentation - Error Log official
- Apache Error Messages official
- Apache Log Levels official
- Troubleshooting Apache Error Logs reference
Generation Configuration
Field Definitions
Complete field reference for this event type with data types, descriptions, and example values.
| Field Name | Type | Required | Format | Description | Example | Possible Values |
|---|---|---|---|---|---|---|
|
timestamp
Source: now() | format_datetime('%a %b %d %H:%M:%S.%f %Y')
|
DateTime | Required |
Day Mon DD HH:MM:SS.microseconds YYYY
|
Date and time when the error occurred, including microseconds |
Fri Dec 20 15:31:09.533710 2025
|
— |
|
log_level
Source: random_choice(['error', 'warn', 'notice', 'info', 'debug', 'crit', 'alert', 'emerg'])
|
String | Required |
Apache log level
|
Severity level of the log entry |
error
|
emerg
— Emergency - System is unusable
alert
— Alert - Action must be taken immediately
crit
— Critical - Critical conditions
error
— Error - Error conditions
warn
— Warning - Warning conditions
notice
— Notice - Normal but significant condition
info
— Informational - Informational messages
debug
— Debug - Debug-level messages
|
|
process_id
Source: random_int(1000, 99999)
|
Integer | Required |
PID
|
Process ID of the Apache worker process that logged the event |
12345
|
— |
|
thread_id
Source: random_int(100000000, 999999999)
|
Integer | Required |
Thread ID
|
Thread ID within the worker process |
139876543210000
|
— |
|
client_ip
Source: random_private_ip()
|
String | Optional |
IPv4 or IPv6
|
IP address of the client that triggered the error (if applicable) |
10.154.52.51
|
— |
|
client_port
Source: random_port(1024, 65535)
|
Integer | Optional |
Port number
|
Source port of the client connection (if applicable) |
54321
|
— |
|
error_code
Source: Embedded in error message
|
String | Optional |
AHxxxxx
|
Apache error code (AHxxxxx format) identifying the specific error type |
AH01630
|
— |
|
error_message
Source: random_choice of realistic Apache error messages
|
String | Required |
Free text
|
Detailed error message describing the issue |
client denied by server configuration
|
— |
|
referer
Source: Optional: random_choice of referer URLs
|
String | Optional |
URL or absent
|
Referring URL that led to the error (if applicable) |
https://apps.example.com/login
|
— |