Hi.I want to prevent brute force attacks(password guessing)
on my system.account lockout threshold should basically specify the number of invalid logon attempts (eg:5)and then the account should be locked out.

Is there any method to achieve this?

Are you talking about ssh or the local console?

How do you do this in SSH?

There is an entry in your /etc/ssh/sshd_config.

I want to do this in the local console.

I think the "Max number of login retries if password is bad" in the login.defs file is what you are looking for.

http://www.linuxlots.com/~dunne//lw....passwords.html
http://weblog.cs.uiowa.edu/22C178s98/etc/login.defs

i donot have anything that says "Max number of login retries if password is bad" in the login.defs file of /etc.

i was also told to do this:
___________________________


Add the following two lines underlined to the /etc/pam.d/system-auth file as shown below:

auth required /lib/security/pam_env.so
auth required /lib/security/pam_tally.so
____________________________________________________ onerr=fail no_magic_root
___________________________
auth sufficient /lib/security/pam_unix.so likeauth nullok
auth required /lib/security/pam_deny.so
account required /lib/security/pam_unix.so
account required /lib/security/pam_tally.so
____________________________________________________ per_user deny=5 no_magic_root reset
____________________________________
account sufficient /lib/security/pam_succeed_if.so uid < 100 quiet
account required /lib/security/pam_permit.so
password requisite /lib/security/pam_cracklib.so retry=3
password sufficient /lib/security/pam_unix.so nullok use_authtok md5 shadow
password required /lib/security/pam_deny.so
session required /lib/security/pam_limits.so
session required /lib/security/pam_unix.so

But at the beginning of /etc/pam.d/system-auth it is mentioned that 'user changes will be destroyed the next time the file is run'.

so if i add my own text to this file,its not getting accepted.

what do i do now?

Again, please check denyhosts

Can i get a more detailed explanation plz.what is it that you want me to check in hosts.deny.when i opened the file,i found nothing there.

sorry to say this but i feel my mail was not read completely.when we don't explain the problem in detail,u complain.i had not just one but two issues there.

Guys my question is still unanswered.will i be getting any help here???

i am using a Fedora core release 3(Heidelberg)

kernel 2.6.9-1.667 on an i686.

Fedora 3 is old, I would upgrade.

I am running Slackware 10.2. There are entries for LOGIN_RETRIES (Max number of login retries if password is bad) /etc/login.defs. I am willing to bet it is in yours too.

I did a google search and came up with this post in this forum. This guy is using RH 9 and has those entries.
http://www.linuxquestions.org/questi...d.php?t=450146

Since Fedora uses PAM, you might want to google for "set max login retries,PAM".

Or you might want to read the man page for login.
Usually when someone does not take the time too google and then get pushy, I say screw then and ignor the thread. Just in case you have not noticed. Non of us get paid here. You do not have to pay to post threads here. So, you should be more respectful when posting here. Strait up, no one here owes you anything. Especially, doing your google research.