man passwd:
o Each password must have PASSLENGTH characters, where
PASSLENGTH is defined in /etc/default/passwd and is set
to 6. Setting PASSLENGTH to more than eight characters
requires configuring policy.conf(4) with an algorithm
that supports greater than eight characters.
o Each password must meet the configured complexity con-
straints specified in /etc/default/passwd.
o Each password must not be a member of the configured
dictionary as specified in /etc/default/passwd.
o For accounts in name services which support password
history checking, if prior password history is defined,
new passwords must not be contained in the prior pass-
word history.
If you're using defaults, then 6 is the maximum number of characters. Also:
MINNONALPHAMinimum number of non-alpha (including
numeric and special) required. If MIN-
NONALPHA is not set, the default is 1.
You cannot specify MINNONALPHA if MINDI-
GIT or MINSPECIAL is also specified.
count it out.
alan