John the ripper configuration problem

[Dante]

Hi all,
first i wanna say that I'm french so i apologize for orthography and syntax.

So i just want to know if it is possible to use a 'mask' when cracking a password with JTR.
For example:

-> i know my password is 15 chars long
-> but i also know the 9 first chars

How can i proceed??

[bofh28]

john won't help you in this case. It is hard coded to support a maximum of 8 characters. If you know for sure the first 9 characters use crunch to generate the words using -t (i think) and feed the results to mdcrack if you are trying to crack lm or ntlm. You also try to use crunch and feed the results to john. What algorithm are you trying to crack?

[Dante]

The pass is MD5 encrypted.
So if i understood well crunch will generate me an exhaustive dico file formated with my 'mask'?
It's similar to a bruteforce, but will it not be longer?