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-
- Customizing John the Ripper
- =============================
-
- John the Ripper's behavior can be customized by editing its configuration
- file, ~/john.ini. You can set global options, define wordlist and "single
- crack" mode rules, define parameters for incremental modes, or even define
- a new cracking mode.
-
- The configuration file consists of several sections. Each section starts
- with a line containing its name, in brackets. Sections consist of either
- value assignments to some variables (in form 'variable = value'), or some
- other text specific to particular section's type (names of such sections
- start with a 'list.'). Section and variable names are not case sensitive.
- Lines starting with '#' or ';' and empty lines are ignored, you can use
- them for comments, or to comment out lines that you don't want to delete
- completely.
-
- General Options
- -----------------
-
- Some global options can be defined in the [Options] section. Currently you
- can set the following:
-
- Wordfile Set to your wordlist file name, to be used in batch mode.
- (That is, when you run John with password files, but not
- specifying a cracking mode.)
-
- Idle If set to 'Y', John will use idle cycles only. Currently
- this is only supported on Linux, if you apply the kernel
- patch found in src/idle.diff. (Note: even though the patch
- is trivial, it is to be considered experimental. You have
- been warned.) When running on Linux without the patch, a
- less efficient implementation, based on sched_yield(), is
- used. On all the other systems this option is equivalent
- to nice(20). By the way, this doesn't affect the startup
- time and non-cracking John runs, as the priority is only
- set before going into the cracking loop.
-
- Save Crash recovery file saving delay in seconds. Adjust this
- when using power-saving, say, on a notebook computer.
-
- Beep If set to 'Y', John will beep when a password is found.
- Why would someone need this, anyway? Still, some people
- requested that I put this feature back in, so it's here.
-
- Defining Wordlist Rules
- -------------------------
-
- The rules for wordlist and "single crack" modes are defined in separate
- sections, [List.Rules:Wordlist] and [List.Rules:Single] respectively. I
- used an extended Crack (by Alec Muffett) syntax, since many of you are
- already familiar with it. I added some more rules, and (most important)
- a preprocessor, which generates multiple rules from a single source line.
-
- When defining rules, simply place one rule (which may include preprocessor
- commands) per line. See doc/RULES for information on rules syntax and the
- preprocessor.
-
- Incremental Mode Parameters
- -----------------------------
-
- To define the incremental mode parameters you need to create a section
- called [Incremental:MODE], where MODE is any identifier that you assign
- to the mode. There're some pre-defined incremental modes in the default
- configuration file supplied with John, you can use them as templates.
-
- The following parameters are supported:
-
- File Set to your charset file name. See doc/EXAMPLES for an
- example on how to generate one.
-
- MinLen Minimum password length, in characters (0 by default).
-
- MaxLen Maximum password length, in characters (CHARSET_LENGTH as
- defined in src/params.h, normally 8, by default).
-
- CharCount Allows you to limit the number of different characters
- used, to make John start trying longer passwords earlier.
- This can also be used to make John print a warning if the
- charset only defines less than CharCount characters. By
- default (when this parameter is not used) all the defined
- characters will be used.
-
- Extra This can be used to make John try some extra characters,
- that don't appear in the charset file. Just list all these
- characters here, they will then be added, but considered
- the least probable.
-
- Defining an External Mode
- ---------------------------
-
- See doc/EXTERNAL.
-