Admins eHow SysAdmin Tips & Tricks

September 1, 2014

Disable ipv6 on Linux

Filed under: linux — Tags: , , — admin @ 10:17 am

To disable ipv6 on Linux, add following line to /etc/sysctl.conf

net.ipv6.conf.all.disable_ipv6 = 1

Now apply the change :

sysctl -p

August 20, 2014

Force public key authentication on SSH daemon (disable password authentication)

Filed under: Debian,linux,Security — Tags: , , , , , , — admin @ 2:18 pm

It is a very good security practice to completely disable password authentication on your Linux server and use public key authentication method.
In order to do that you need to create your own public/private key pair and put the public key in ~/.ssh/authorized_keys

mkdir -p ~/.ssh
echo 'ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDHV80zPWjPAwKo8Be0k1ypBRMdYDC0H2eQchu3MFsEp8av2F/18GNuHsbyMWp0p1uovP5LGZ/oPZ1ISJxLxxOBiqv0fOyb8uTDYWUUITgGvq9Fppj3BNYTjnLCUAVMKdP3VJ7IPk69ygYR1nhAXiv3dSfeG74f2eo3ZYhrylsVS2G84DUh47FuEFOsfn5s2wXVjwAgqdKBhiVQZWrptf6TEK3fZTVg4rCiRJ+YiIwTZr/CfFHbdqOiwDlGR5fWo0PHHq31lrQXzkASfi3C+ahQFnHsy4+8LdCq+TjzC3J6PbuXP1wpLdm1iP35f61hU1wX2hwhyxdvE+SBXT/PpSVB' >> ~/.ssh/authorized_keys

DISCLAIMER : The above key is my public key, if you put it on your server, I will be able to login into your server 😀
Now add/change the following config to /etc/ssh/sshd_config

ChallengeResponseAuthentication no
PasswordAuthentication no
UsePAM no
PubkeyAuthentication yes

and restart ssh service :

service ssh restart

Note : Before closing your current SSH session, I highly recommend you to test that actually you can login into your server by new method. otherwise you may be locked out of your server.

March 31, 2011

Disable WordPress Commenting System to prevent spam

Filed under: General,Security,WordPress — Tags: , , , , , — admin @ 11:01 am

It is a few days that I have installed Disqus wordpress plugin and I am quite impressed by it. I am receiving no more spam/bot messages through Disqus commenting system , but still bots are able to send spam to wordpress own commenting system ! so I was looking for a solution to disable wordpress comments and I found the following link :

http://beta.beantin.se/wordpress-comment-spam-disqus/

it provides 2 solutions to get rid of wordpress commenting system , but I prefer the neat one ! delete the whole thing ! lol
simply delete wp-comments-post.php from your wordpress root installation folder. then bots can go to hell 😉

March 20, 2010

How to Disable Password Expiration on Windows Server 2008

Filed under: General,Security,Windows — Tags: , , , , , — admin @ 2:31 pm

If you’re not using Active Directory, your “Local Security Policy” dictates things like password complexity rules, account lockouts, and password expiration. To turn off password expiration:

1) Login as Administrator or a user with Administrator rights
2) Launch “Local Security Policy”: Start > Administrative Tools > Local Security Policy
3) Expand “Account Policies”
4) Select Password Policy
5) Set Maximum Password age to “0”

Source : Ryan’s Tech Notes

July 30, 2009

Disable submit button on click

Filed under: HTML,JavaScript — Tags: , , , , — admin @ 10:50 am

Are you looking for a JavaScript code to disable your HTML form submit button on first click to prevent double clicks ?
so here is the code 🙂 , it has been tested on IE 8 , Firefox 3.5 and Chrome. I am pretty sure it works on all browsers which support JavaScript.
Put the following code into <head> section of your page :

<script language="javascript" type="text/javascript">
function dis(){
frm=document.forms[0];
frm.submit.disabled=true;
}
</script>

and the following code into <form> section :

onsubmit="dis();"

for example :

<form method="post" action="/index.php" onsubmit="dis();">

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