Linux Passwords

I am running a Red Hat 6.1 box supporting only a few users. It is rejecting one of the passwords I am trying to assign a user. It is actually an alpha-numeric password, so I am not sure why it does not like it. I changed it to something else thatit did accept, but I would like to be able to use any password I want. I am not too concerned with security. Is there a way to take off anything that limits either password length or dictionary words and such. Thanks.