SPAMORACLE.CONF(5)SPAMORACLE.CONF(5)NAMEspamoracle.conf - SpamOracle configuration file format
DESCRIPTION
The spamoracle.conf file is a configuration file governing the opera‐
tion of the spamoracle(1) e-mail classification tool. By default, the
configuration file is searched in $HOME/.spamoracle.conf but an alter‐
nate location can be specified using the -config flag to spamoracle(1).
Important note: most of the configuration parameters should not be mod‐
ified lightly, as this may result in completely wrong e-mail classifi‐
cation. Familiarity with Graham's filtering algorithm, as described in
the paper referenced at the end of this page, is required to really
understand the effect of the parameters.
SYNTAX
The spamoracle.conf file is composed of lines of the form variable =
value. Lines starting with a hash sign (#) are treated as comments and
ignored. Blank lines are ignored.
Depending on the type of the variable (see the list of variables
below), the value part is of the following forms:
string A sequence of characters. Blanks (spaces, tabs) at the begin‐
ning and the end of the string are ignored. Alternatively, the
string can be enclosed in double quotes ("), in which case spa‐
ces are not trimmed. Inside quoted strings, blackslashes ( and
double quotes (") must be escaped with a backslash, as in \ or
boolean
Either on, yes, true, or 1 to activate the boolean option, or
off, no, false, or 0 to deactivate it.
integer
A decimal integer
float A decimal floating-point number.
regexp A regular expression in emacs(1) syntax. The repetition opera‐
tors are *, +, and ?. Alternation is written \| and grouping is
written \(...\). Character classes are written between brackets
[...] as usual. A single dot denotes any character except new‐
line. Regular expressions are case-insensitive.
CONFIGURABLE PARAMETERS
database_file
(type string, default value $HOME/.spamoracle.db )
The location of the file that contains the database of word fre‐
quencies used by spamoracle(1).
html_retain_tags
(type boolean, default value false)
In HTML-formatted e-mails and attachments, the names of HTML
tags are normally not treated as words and are ignored for the
word frequency calculations. If the html_retain_tags parameter
is set to true, HTML tags (such as img or bold) are treated as
words and included in the computation of word frequencies.
html_tag_attributes
(type regexp, default value
a/href\|img/src\|img/alt\|frame/src\|font/face\|font/color)
This regular expression matches pairs of HTML tags and HTML
attributes written as tag/attribute. When scanning HTML-format‐
ted e-mails and attachments, attributes to HTML tags are nor‐
mally ignored, unless the tag/attribute pair matches the regular
expression html_tag_attributes. If the tag/attribute pair
matches this regexp, the value of the attribute (for instance,
the URL for the a/href attribute) is scanned for words.
mail_headers
(type regexp, default value from:\|subject:)
A regular expression determining which headers of an e-mail mes‐
sage are scanned for words.
spam_header
(type string, default value X-Spam)
The name of the header that spamoracle mark adds to incoming e-
mail messages, with the results of the spam/non-spam classifica‐
tion.
attachments_header
(type string, default value X-Attachments)
The name of the header that spamoracle mark adds to incoming e-
mail messages, with the one-line summary of attachment types,
names and character sets. The generation of this header can be
turned off with the summarize_attachment parameter.
summarize_attachment
(type boolean, default value true)
If this parameter is set, spamoracle mark generates a one-line
summary of the attachments of the incoming messages, and inserts
this summary in the message headers. Setting this parameter to
false disables the generation of this extra header.
num_meaningful_words
(type integer, default value 15)
Maximal number of "meaningful" words that are retained for com‐
puting the spam probability. During mail analysis, spamoracle
extracts all words of the message, and retains those whose spam
frequency (frequency of occurrence in spam messages) is closest
to 1 or to 0. At most num_meaningful_words such "meaningful"
words are retained.
max_repetitions
(type integer, default value 2)
Maximum number of times a given word can occur in the set of
"meaningful" words retained for computing the spam probability.
The default value of 2 means that at most 2 occurrences of the
same word will be retained.
low_freq_limit
(type float, default value 0.01)
high_freq_limit
(type float, default value 0.99)
The spam frequency of a word is computed as the number of occur‐
rences in spam divided by number of occurrences in all messages.
This ratio is then clipped to the interval [ low_freq_limit,
high_freq_limit ], so that words that are extremely rare or
extremely common in spam do not bias the probability computation
too much. The default values of 0.01 and 0.99 are adequate for
a corpus of a few thousand e-mails. For larger corpora (e.g.
10000 e-mails), the values 0.001 and 0.999 may give better
results.
min_meaningful_words
(type integer, default value 5)
Minimum number of "meaningful" words below which spamoracle mark
refuses to classify the e-mail and outputs "unknown" status.
This happens with very short e-mails, or e-mails that consist
exclusively of links and pictures.
good_mail_prob
(type float, default value 0.2)
Spam probability below which the e-mail is classified as non-
spam.
spam_mail_prob
(type float, default value 0.8)
Spam probability above which the e-mail is classified as spam.
Messages whose probability falls between good_mail_prob and
spam_mail_prob are classified as "unknown".
AUTHOR
Xavier Leroy <Xavier.Leroy@inria.fr>
SEE ALSOspamoracle(1)
http://www.paulgraham.com/spam.html (Paul Graham's seminal paper)
SPAMORACLE.CONF(5)
