Conditions are used to apply a rule to a message. You can decide if a message must fulfill all conditions or at least one condition. Here's a list of all available conditions:
Any Message
This is true for any incoming message. (Use this to apply a standard action to any message)
Messages with [specified words] in the subject
A message fulfills this condition if its subject contains the word or phrase you specified.
Messages with [specified words] in the From header
A message fulfills this condition if its From header contains the word or phrase you specified.
Messages with [specified words] in the To header
A message fulfills this condition if its To header contains the word or phrase you specified.
Messages with [specified words] in the Cc header
A message fulfills this condition if its Cc header contains the word or phrase you specified.
Messages with a recipient address containing parts like ...
A message fulfills this condition if its SMTP recipient address contains the phrases you specified.
Messages with [specified words/phrases] in the header
A message fulfills this condition if its header contains the word or phrase you specified.
Messages with [specified words] in the body
A message fulfills this condition if its body contains the word or phrase you specified.
Messages with no subject
A message fulfills this condition if its subject is empty.
Messages containing a virus
A message fulfills this condition if ClamAV or your installed anti-virus software detects a virus in one of its attachments (See also settings)
Messages declared as spam
A message fulfills this condition if SpamAssassin rates the message with a value higher than the Spam threshold you specified. (See here for more information)
Messages with a size greater than [specified]
A message fulfills this condition if it is larger than the specified size.
Messages with [any] attachment
A message fulfills this condition if it has at least one attachment. It is also possible to set a mask for special attachments like *.mp3.
This mask can also match files in ZIP archives if the appropriate option is checked.
Messages has attachment with a size greater than [specified]
A message fulfills this condition if it has at least one attachment with a size greater than what you specified.
The test for words, phrases or addresses that trigger conditions is case-insensitive. (e.g. 'JAM-Software' and 'jam-software' will be handled equally).
Also, the test for words, phrases or addresses can be configured as regular expression.