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  #1 (permalink)  
Old 09-16-2009
shamik shamik is offline
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Posts: 22
Unhappy Increase Password length

Hello All,

I am using RHEL 4. Currently maximum password length limit is set to 8 on my system.

Please tell what do i need to change to increase this limit to say 20. I changed the login.defs and included the following line -
"
PASS_MAX_LEN 20
"
but this dint work.

I further modified /etc/pam.d/system-auth file and added there too as-

"
password sufficient /lib/security/$ISA/pam.unix.so nullok maxlen=20 use_authtok md5 shadow
"

but this too doest work.

Can anyone please tell me how to increase the password length.


Thanks and Regards,
Shamik.
  #2 (permalink)  
Old 09-16-2009
Franklin52 Franklin52 is offline Forum Staff  
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Posts: 4,305
Check the /etc/default/security file for system wide settings.
Note that despite the possibility to use more characters, only the first 8 are used.

Regards
  #3 (permalink)  
Old 09-16-2009
shamik shamik is offline
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Posts: 22
Can you please tell in brief what does the following mean -

"Note that despite the possibility to use more characters, only the first 8 are used."

The security directory is present in /etc directory in my system and following are its contents -

console.apps/
access.conf
chroot.conf
console.perms
group.conf
limits.conf
opasswd
pam_env.conf
pam_winbind.conf
time.conf

There is no file called security in /etc/default
  #4 (permalink)  
Old 09-16-2009
jim mcnamara jim mcnamara is offline Forum Staff  
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Quote:
"Note that despite the possibility to use more characters, only the first 8 are used."
This means:
password hashing uses the first 8 characters of the password, the rest are ignored.
  #5 (permalink)  
Old 09-16-2009
Corona688 Corona688 is online now
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Quote:
Originally Posted by jim mcnamara View Post
This means:
password hashing uses the first 8 characters of the password, the rest are ignored.
I don't get it. My root password is almost twice as long, and mistyping any of the characters after the eighth makes a failed login. Unless this is some odd redhat-specific thing...
  #6 (permalink)  
Old 09-16-2009
jim mcnamara jim mcnamara is offline Forum Staff  
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A lot of older versions of unix don't support more than 8 characters. HPUX 10.2 for example. Stevens 'Advanced Programming in the UNIX Environment' mentions it as well. Red Hat out of the box hashes a maximum of 8; here is a discussion explaining changing PAM etc. to increase the password length:

Red Hat Knowledgebase: How do I change the default password length?

I have not used RHEL 4 so I assumed this was true.
  #7 (permalink)  
Old 09-25-2009
arm_naja arm_naja is offline
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Quote:
Originally Posted by jim mcnamara View Post
A lot of older versions of unix don't support more than 8 characters. HPUX 10.2 for example. Stevens 'Advanced Programming in the UNIX Environment' mentions it as well. Red Hat out of the box hashes a maximum of 8; here is a discussion explaining changing PAM etc. to increase the password length:

Red Hat Knowledgebase: How do I change the default password length?

I have not used RHEL 4 so I assumed this was true.
on my RHEL5.2

it not work, why ??
===
entry in /etc/pam.d/system-auth
password requisite pam_cracklib.so try_first_pass retry=3 minlen=8
===
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