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traceoptions (DNS, Port, and TFTP Packet Forwarding)



Hierarchy Level

Release Information

Statement introduced before Junos OS Release 7.4.

Statement standardized and match option introduced in Junos OS Release 8.0.


Configure tracing operations for BOOTP, DNS, TFTP, or custom UDP port packet forwarding.


If you do not include this statement, no tracing operations are performed.


file filename—Name of the file to receive the output of the tracing operation. Enclose the name in quotation marks (" "). All files are placed in a file named fud in the directory /var/log. If you include the file statement, you must specify a filename.

files number—(Optional) Maximum number of trace files. When a trace file named trace-file reaches its maximum size, it is renamed trace-file.0, then trace-file.1, and so on, until the maximum number of trace files is reached. Then the oldest trace file is overwritten.

If you specify a maximum number of files, you also must specify a maximum file size with the size option and a filename.

Range: 2 through 1000

Default: 3 files

flag flag—Tracing operation to perform. To specify more than one tracing operation, include multiple flag statements. You can include the following flags:

  • address—Trace address management events

  • all—Trace all events

  • bootp—Trace BOOTP or DHCP services events

  • config—Trace configuration events

  • domain—Trace DNS service events

  • ifdb—Trace interface database operations

  • io—Trace I/O operations

  • main—Trace main loop events

  • port—Trace arbitrary protocol events

  • rtsock—Trace routing socket operations

  • tftp—Trace TFTP service events

  • trace—Trace tracing operations

  • ui—Trace user interface operations

  • util—Trace miscellaneous utility operations

match regular-expression—(Optional) Refine the output to include lines that contain the regular expression.

no-remote-trace—(Optional) Disable remote tracing globally or for a specific tracing operation.

no-world-readable—(Optional) Restrict file access to the owner.

size size—(Optional) Maximum size of each trace file, in kilobytes (KB), megabytes (MB), or gigabytes (GB). When a trace file named trace-file reaches this size, it is renamed trace-file.0. When the trace-file file again reaches its maximum size, trace-file.0 is renamed trace-file.1 and trace-file is renamed trace-file.0. This renaming scheme continues until the maximum number of trace files is reached. Then the oldest trace file is overwritten.

If you specify a maximum file size, you also must specify a maximum number of trace files with the files option and filename.

Syntax: xk to specify KB, xm to specify MB, or xg to specify GB

Range: 0 bytes through 4,294,967,295 KB

Default: 128 KB

world-readable—(Optional) Enable unrestricted file access.

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.