Manage Logs
Tenable Nessus has the following default log files:
-
nessusd.dump — Nessus dump log file used for debugging output.
Configure nessusd.dump
-
Open the nessuscli utility.
-
Use the command # nessuscli fix --set setting=value to configure the following settings:
Name
Setting Description
Default Valid Values Nessus Dump File Location dumpfile Location of nessusd.dump, a log file for debugging output if generated.
The following are the defaults for each operating system:
Linux:
/opt/nessus/var/nessus/logs/nessusd.dump
macOS:
/Library/Nessus/run/var/nessus/logs/nessusd.dump
Windows:
C:\ProgramData\Tenable\Nessus\nessus\logs\nessusd.dump
Nessus log directory for your operating system
String Nessus Dump File Log Level nasl_log_type The type of NASL engine output in nessusd.dump.
normal normal, none, trace, or full. Nessus Dump File Max Files dumpfile_max_files The maximum number of the nessusd.dump files kept on disk. If the number exceeds the specified value, Tenable Nessus deletes the oldest dump file. 100 Integers 1-1000 Nessus Dump File Max Size dumpfile_max_size The maximum size of the nessusd.dump files in MB. If file size exceeds the maximum size, Tenable Nessus creates a new dump file. 512 Integers 1-2048 Use Milliseconds in Logs logfile_msec When enabled, nessusd.messages no yes or no For more information, see Advanced Settings.
-
-
nessusd.messages — Nessus scanner log.
Configure nessusd.messages
-
Open the agent command line interface.
-
Use the command # nessuscli fix --set setting=value to configure the following settings:
Name
Setting Description
Default Valid Values Nessus Scanner Log Location logfile Location where Tenable Nessus stores its scanner log file.
The following are the defaults for each operating system:
Linux:
/opt/nessus/var/nessus/logs/nessusd.messages
macOS:
/Library/Nessus/run/var/nessus/logs/nessusd.messages
Windows:
C:\ProgramData\Tenable\Nessus\nessus\logs\nessusd.messages
Nessus log directory for your operating system String Log File Rotation logfile_rot Determines whether Tenable Nessus rotates messages log files based on maximum rotation size or rotation time.
size size — Tenable Nessus rotates log files based on size, as specified in logfile_max_size.
time — Tenable Nessus rotates log files based on time, as specified in logfile_rotation_time.
Use Milliseconds in Logs logfile_msec When enabled, nessusd.messages no yes or no For more information, see Advanced Settings.
-
-
www_server.log — Nessus web server log.
Configure www_server.log
You can configure log locations and rotation strategies for www_server.log by editing the log.json file. You can also configure custom logs by creating a new reporters[x].reporter section and creating a custom file name.
To modify log settings using log.json:
-
Using a text editor, open the log.json file, located in the corresponding directory:
Operating System Log Location Windows C:\ProgramData\Tenable\Nessus\nessus\logs\<filename> macOS /Library/Nessus/run/var/nessus/logs/<filename> Linux /opt/nessus/var/nessus/logs/<filename> -
For each log file, edit or create a reporters[x].reporter section, and add or modify the following parameters:
Note: The following describe parameters in the log.json file, and whether Tenable recommends that you modify the parameter. Some parameters are advanced and you do not need to modify them often. If you are an advanced user who wants to configure a custom log file with advanced parameters, see the knowledge base article for more information.
Parameter Default value Can be modified? Description tags response
no
Determines what log information the log includes.
-
response — Web server activity logs
Note: response is the only valid tag for www_server.log.
type file not recommended Determines the type of the log file. rotation_strategy size yes Determines whether the log archives files based on maximum rotation size or rotation time.
Valid values:
- size — Rotate the log based on size, as specified in max_size.
- daily — Rotate the log based on time, as specified in rotation_time.
rotation_time 86400 (1 day) yes Rotation time in seconds.
Only used if rotation_strategy is daily.
max_size Tenable Nessus: 536870912 (512 MB)
Tenable Nessus Agent: 10485760 (10 MB)
yes Rotation size in bytes.
Only used if rotation_strategy is size.
max_files Tenable Nessus:
Tenable Nessus Agent: 2
yes Maximum number of files allowed in the file rotation.
The maximum number includes the main file, so 10 max_files is 1 main file and 9 backups. If you decrease this number, Tenable Nessus deletes the old logs.
file Depends on operating system and log file
yes The location and name of the log file. See Default Log Locations.
If you change the name of a default Tenable Nessus log file, some advanced settings may not be able to modify the log settings.
context true not recommended Enables more context information for logs in the system format, such as backend.log. format combined not recommended Determines the format of the output.
- combined — Presents output in a format used for web server logs.
- system — Presents output in the default operating system log format.
The following are examples of a log.json file.
Linux example
{
"reporters": [
{
"tags": [
"response"
],
"reporter": {
"type": "file",
"rotation_strategy": "daily",
"rotation_time": "86400",
"max_size": "536870912",
"max_files": "1024",
"file": "/opt/nessus/var/nessus/logs/www_server.log"
},
"format": "combined"
},
{
"tags": [
"log",
"info",
"warn",
"error",
"trace"
],
"reporter": {
"type": "file",
"file": "/opt/nessus/var/nessus/logs/backend.log"
},
"context": true,
"format": "system"
}
]
}
Windows example
Note: The backslash (\) is a special character in JSON. To enter a backslash in a path string, you must escape the first backslash with a second backslash so the path parses correctly.
{
"reporters": [
{
"tags": [
"response"
],
"reporter": {
"type": "file",
"rotation_strategy": "daily",
"rotation_time": "86400",
"max_size": "536870912",
"max_files": "1024",
"file": "C:\\ProgramData\\Tenable\\Nessus\\nessus\\logs\\www_server.log"
},
"format": "combined"
},
{
"tags": [
"log",
"info",
"warn",
"error",
"trace"
],
"reporter": {
"type": "file",
"file": "C:\\ProgramData\\Tenable\\Nessus\\nessus\\logs\\backend.log"
},
"context": true,
"format": "system"
}
]
}
macOS example
{
"reporters": [
{
"tags": [
"response"
],
"reporter": {
"type": "file",
"rotation_strategy": "daily",
"rotation_time": "86400",
"max_size": "536870912",
"max_files": "1024",
"file": "/Library/Nessus/run/var/nessus/logs/www_server.log"
},
"format": "combined"
},
{
"tags": [
"log",
"info",
"warn",
"error",
"trace"
],
"reporter": {
"type": "file",
"file": /Library/Nessus/run/var/nessus/logs/backend.log"
},
"context": true,
"format": "system"
}
]
}
-
- Save the log.json file.
-
Restart the Tenable Nessus service.
The Tenable Nessus updates the log settings.
-
-
backend.log — Nessus backend log.
Configure backend.log
You can configure log locations and rotation strategies for backend.log by editing the log.json file. You can also configure custom logs by creating a new reporters[x].reporter section and creating a custom file name.
To modify log settings using log.json:
-
Using a text editor, open the log.json file, located in the corresponding directory:
Operating System Log Location Windows C:\ProgramData\Tenable\Nessus\nessus\logs\<filename> macOS /Library/Nessus/run/var/nessus/logs/<filename> Linux /opt/nessus/var/nessus/logs/<filename> -
For each log file, edit or create a reporters[x].reporter section, and add or modify the following parameters:
Note: The following describe parameters in the log.json file, and whether Tenable recommends that you modify the parameter. Some parameters are advanced and you do not need to modify them often. If you are an advanced user who wants to configure a custom log file with advanced parameters, see the knowledge base article for more information.
Parameter Default value Can be modified? Description tags log, info, warn, error, trace
yes
Determines what log information the log includes.
-
response — Web server activity logs
- info — Informational logs for a specific task
- warn — Warning logs for a specific task
- error — Error logs for a specific task
- debug — Debugging output
- verbose — Debugging output with more information than debug
- trace — Logs used to trace output
type file not recommended Determines the type of the log file. rotation_strategy size yes Determines whether the log archives files based on maximum rotation size or rotation time.
Valid values:
- size — Rotate the log based on size, as specified in max_size.
- daily — Rotate the log based on time, as specified in rotation_time.
rotation_time 86400 (1 day) yes Rotation time in seconds.
Only used if rotation_strategy is daily.
max_size Tenable Nessus: 536870912 (512 MB)
Tenable Nessus Agent: 10485760 (10 MB)
yes Rotation size in bytes.
Only used if rotation_strategy is size.
max_files Tenable Nessus:
Tenable Nessus Agent: 2
yes Maximum number of files allowed in the file rotation.
The maximum number includes the main file, so 10 max_files is 1 main file and 9 backups. If you decrease this number, Tenable Nessus deletes the old logs.
file Depends on operating system and log file
yes The location and name of the log file. See Default Log Locations.
If you change the name of a default Tenable Nessus log file, some advanced settings may not be able to modify the log settings.
context true not recommended Enables more context information for logs in the system format, such as backend.log. format combined system
not recommended Determines the format of the output.
- combined — Presents output in a format used for web server logs.
- system — Presents output in the default operating system log format.
The following are examples of a log.json file.
Linux example
{
"reporters": [
{
"tags": [
"response"
],
"reporter": {
"type": "file",
"rotation_strategy": "daily",
"rotation_time": "86400",
"max_size": "536870912",
"max_files": "1024",
"file": "/opt/nessus/var/nessus/logs/www_server.log"
},
"format": "combined"
},
{
"tags": [
"log",
"info",
"warn",
"error",
"trace"
],
"reporter": {
"type": "file",
"file": "/opt/nessus/var/nessus/logs/backend.log"
},
"context": true,
"format": "system"
}
]
}
Windows example
Note: The backslash (\) is a special character in JSON. To enter a backslash in a path string, you must escape the first backslash with a second backslash so the path parses correctly.
{
"reporters": [
{
"tags": [
"response"
],
"reporter": {
"type": "file",
"rotation_strategy": "daily",
"rotation_time": "86400",
"max_size": "536870912",
"max_files": "1024",
"file": "C:\\ProgramData\\Tenable\\Nessus\\nessus\\logs\\www_server.log"
},
"format": "combined"
},
{
"tags": [
"log",
"info",
"warn",
"error",
"trace"
],
"reporter": {
"type": "file",
"file": "C:\\ProgramData\\Tenable\\Nessus\\nessus\\logs\\backend.log"
},
"context": true,
"format": "system"
}
]
}
macOS example
{
"reporters": [
{
"tags": [
"response"
],
"reporter": {
"type": "file",
"rotation_strategy": "daily",
"rotation_time": "86400",
"max_size": "536870912",
"max_files": "1024",
"file": "/Library/Nessus/run/var/nessus/logs/www_server.log"
},
"format": "combined"
},
{
"tags": [
"log",
"info",
"warn",
"error",
"trace"
],
"reporter": {
"type": "file",
"file": /Library/Nessus/run/var/nessus/logs/backend.log"
},
"context": true,
"format": "system"
}
]
}
-
- Save the log.json file.
-
Restart the Tenable Nessus service.
The Tenable Nessus updates the log settings.
-
- nessuscli.log — Nessuscli log.
Default Log Locations
The following table describes the default log file locations for each operating system.
| Operating System | Log Location |
|---|---|
| Windows | C:\ProgramData\Tenable\Nessus\nessus\logs\<filename> |
| macOS | /Library/Nessus/run/var/nessus/logs/<filename> |
| Linux | /opt/nessus/var/nessus/logs/<filename> |