nixCraft » Linux login control

7 Powerful Firefox Password Managers [ Add-ons ]

nixCraft — Mon, 08 Dec 2008 09:02:41 +0000

Choosing the password is only the first step; you have got to remember it. You can not remember 100s of password at a time. However, with the help of a password manager, you can organize passwords, host names, and PIN codes.

Like most of you, I love using Firefox and explaining the advantages of Firefox to others who use other browsers. Unlike other browsers, Firefox has huge list of excellent add-ons that will satisfy almost all of your requirements in using a browser. Following are the list of 7 powerful Firefox password related add-ons that will make your life in managing passwords very safe, secure and easy under Mac OS X, Linux / UNIX and Windows operating system.

pssh: Run Command On Multiple SSH Servers

nixCraft — Sat, 01 Nov 2008 19:44:16 +0000

I've already written about tentakel tool and shell script hack to run a single command on multiple Linux / UNIX / BSD server. This is useful to save time and run UNIX commands on multiple machines. Linux.com has published an article about a new tool called pssh:

If you want to increase your productivity with SSH, you can try a tool that lets you run commands on more than one remote machine at the same time. Parallel ssh, Cluster SSH, and ClusterIt let you specify commands in a single terminal window and send them to a collection of remote machines where they can be executed.

Emergency Server Management With Intelligent Platform Management Interface (IPMI)

nixCraft — Wed, 07 May 2008 18:49:24 +0000

Intelligent Platform Management Interface (IPMI) is a hardware level interface specification that defines a common, abstracted, message-based interface to platform monitoring and control functions. Both IPMI and KVM over IP can be used in emergency situations.

How to: Install KDE 4 Desktop under Ubuntu Linux 7.10

nixCraft — Sun, 20 Jan 2008 19:16:08 +0000

KDE 4 has been released. I've received couple of questions about installing KDE 4 under Ubuntu Linux 7.10. KDE 4 Packages are available for Ubuntu Linux version 7.10 (Gutsy) and from development Ubuntu Linux Hardy version. They install to /usr/lib/kde4 and can be installed alongside your existing KDE 3. However these packages are not compatible [...]

When a user logs in what files are updated in UNIX / Linux

nixCraft — Tue, 02 Oct 2007 20:07:00 +0000

One of our regular reader asks: I’d like to discover information about who is currently using the system. When a user logs in what files are updated in UNIX / Linux? Linux / UNIX have utmp and wtmp files to keep login records. Following three files keeps track of all logins and logouts to the [...]

Linux allow / restrict system logins to specific user groups only using pam_listfile PAM module

nixCraft — Thu, 13 Sep 2007 07:55:13 +0000

There are two ways to allow / restrict system login to specific user groups only. The simplest method is to use a PAM module called pam_listfile.so. Another option is to use login access control table. Locking down system login access is very important task if you need a secure system. The system administrator is free [...]

Increase the maximum number of pseudo – terminals ~ PTY on Linux for remote Login session

nixCraft — Tue, 11 Sep 2007 07:04:21 +0000

Generally service such as ssh, screen, expect, telnet etc use pty (pseudo-terminals) in master – slave mode for login and other purposes. If pty setting is too low many users will not able to login to system using ssh or other commands. In this tip I will explain how to increase the maximum number of [...]

Setup OpenLDAP authentication on Linux for OSX Client and sync / share home directory

nixCraft — Tue, 28 Aug 2007 15:29:18 +0000

Finally, someone spends time to work with a Linux server and OS X authentication issue: OSX has what I would call an undocumented feature of the operating system- the portable home directory. Basically, it keeps a user's home directory sync'd up between a network share and the local pc. If you are not on the [...]

Download of the day: SSH Menu ~ Save and Open SSH Connections on a single mouse click

nixCraft — Mon, 20 Aug 2007 10:28:59 +0000

For last couple of years I’ve used my own shell script based solution to list and open ssh connections. Now I found a nice applet called SSHMenu: The SSHMenu is a panel applet that makes all your regular SSH connections a single mouse click away. Each menu option will open an SSH session in a [...]

Linux configure point to point tunneling PPTP VPN client for Microsoft PPTP vpn server

nixCraft — Mon, 11 Jun 2007 19:21:58 +0000

With this tip you will be able to work from home using VPN and that too from Linux / FreeBSD system for the proprietary Microsoft Point-to-Point vpn server. Different organization uses different VPN connection options such as SSL, PPTP or IPSEC. When you need to access corporate network and its services, you need to login [...]

What is the difference between password and passphrase under OpenSSH with DSA / RAS public key authentication?

nixCraft — Tue, 22 May 2007 15:25:43 +0000

Recently I received an interesting question from one my regular reader: What is the basic and important difference between password and passphrase when implementing SSH with DSA/RAS public key authentication? Which one is recommended for daily usage? The main and basic difference is that you can use multi string phrase including spaces and tabs using [...]

Howto use multiple SSH keys for password less login

nixCraft — Mon, 14 May 2007 00:19:51 +0000

A step by step guide on setting up multiple SSH keys for password less login.

Howto prevent non-root users from login into the system using nologin shell

nixCraft — Thu, 16 Nov 2006 18:23:55 +0000

How do you prevent non-root users from login into the system? How do you assign user ftp and mail access only? How do you make or set shell to nologin to politely refuse a login? Fear not, it is easy to deny access to login shell :D . If the file /etc/nologin exists, login will [...]

Restrict the use of su command

nixCraft — Thu, 16 Nov 2006 17:56:48 +0000

su is used to become another user during a login session. Invoked without a username, su defaults to becoming the super user. The user will be prompted for a password, if appropriate. Invalid passwords will produce an error message. All attempts, both valid and invalid, are logged to detect abuses of the system. By default [...]

Force OpenSSH (SSHD) to use authentication via LDAP server

nixCraft — Mon, 06 Nov 2006 13:34:05 +0000

Lightweight Directory Access Protocol, or LDAP , is a directory services running over TCP/IP. Most large business and organization use LDAP for centralized authentication. You can read LDAP Linux HOWTO for setup and configuration. If your workstation or server setup to authenticate via LDAP, open ssh will not work when user try to connect from [...]

Force OpenSSH (sshd) to listen on selected multiple IP address only

nixCraft — Sat, 28 Oct 2006 15:53:45 +0000

So how do you force sshd to listen on multiple IP addresses? Let us say you have total 8 public IP address and one private IP address. You would like to bind sshd to one selected public IP (ex 70.5.xx.xx) and private IP (10.1.5.1) only. Luckily there is an easy way to achieve this using [...]

OpenSSH Root user account restriction – revisited

nixCraft — Wed, 02 Aug 2006 19:13:21 +0000

One of our article generated few more question regarding root login issues over ssh session. One of reader (eMBee) asks, "I need something that allows me to say: allow any users except root from anywhere, and root only from localhost. (over ssh session)". PAM offers very powerful authentication control. You need to use the pam_access [...]

Linux PAM configuration that allows or deny login via the sshd server

nixCraft — Sun, 30 Jul 2006 18:13:40 +0000

The idea is very simple you want to limit who can use sshd based on a list of users. The text file contains a list of users that may not log in (or allowed to log in) using the SSH server. This is used for improving security. PAM (Pluggable authentication modules) allows you to define [...]

Linux last reboot time and date find out

nixCraft — Sun, 30 Apr 2006 16:34:00 +0000

So how do you find Linux / UNIX system last reboot or shutdown date and time? The last utility will either list the sessions of specified users, ttys, and hosts, in reverse time order, or list the users logged in at a specified date and time. Each line of output contains the user name, the [...]

Howto: Linux shell restricting access

nixCraft — Wed, 08 Feb 2006 15:49:00 +0000

By default when you add new user to system (/etc/passwd file) it grant shell access. If you are creating new users for POP3 or SMTP (mail server) or FTP then you do not need to grant shell access to a user. Remember as soon as you add a user he/she can login via telnet or [...]