Debuntu

This tutorial will show how you can export and import a set of GPG keys from one computer to another.
This way, you can sign/encrypt the same way one different computer.

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This tutorial will explain how to create a self-signed certificate that you will be able to use with apache in order to provide ssl support.

A self signed certificate won’t provide as much security guarantees than a CA-signed certificate, but at least you will be able to use encrypted connection to your server.

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This tutorial will show how-to connect to a Cisco VPN Concentrator using vpnc.

vpnc is a VPN client compatible with cisco3000 VPN Concentrator which runs in userspace and uses the tun kernel module.

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SNMP (Simple Network Management Protocol) is a protocol for managing networks. Each managed entity in the network will run an snmp server (snmpd) which is going to collect datas from the server such as networking, load, cpu …

Cacti on the other hand is a frontend to the RRDTool with SNMP support. It collects and keep data in a MySQL database and display them through a PHP web frontend.

This tutorial will show how to configure the network manager to use Cacti and how to set up snmp on the managed host.

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3. Adding new devices to cacti

A device can be anything which is SNMP enabled. It could be a router, a switch….

In our example, we are going to add the server we configured in the first part of this tutorial. The server is on localhost, but it could be anywhere on a network, as long as our manager host is allowed to connect to its SNMP port.

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Now that we have our snmp server up and running, we are going to install cacti to manage the snmp server in our network.

2. Installing Cacti

Cacti displays system statistics through a PHP/MySQL web interface.

To gather informations, it runs a script which is going to poll the servers you registered in cacti: /usr/share/cacti/site/poller.php.

So, let’s get started an install cacti.

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MySQL is a widely spread SQL database management system mainly used on LAMP (Linux/Apache/MySQL/PHP) projects.

In order to be able to use a database, one needs to create: a new database, give access permission to the database server to a database user and finally grant all right to that specific database to this user.

This tutorial will explain how to create a new database and give a user the appropriate grant permissions.

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2. Configuring the clients

Each client will need a set of packages. So, now that you are logged on one of your clients, install:

#apt-get install libnss-ldap libpam-ldap nscd
LDAP Account for root: cn=admin,dc=debuntu,dc=local
Password: XXXX
Make local root database admin: yes
Database require logging in: No
Root login account: cn=admin,dc=debuntu,dc=local
Root login password: XXXX

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LDAP (Lightweight Directory Access Protocol) allows central user, group, domain….. authentication, information storage …

Using LDAP in a local network, you can allow your users to login and authenticate from anywhere on your network.

This tutorial will be split in 2 parts. In the first part, I will explain how-to install, configure the LDAP server, add a few users and group, in the second part, we will set up Linux client to authenticate through LDAP if the user does not exist on the local filesystem.

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4. Disabling Authentication by password

In order to disable authentication by password, we need to connect as root on the remote machine. On connected, go and edit /etc/ssh/sshd_config and make sure you have the following setting:

….
ChallengeResponseAuthentication no
PasswordAuthentication no
UsePAM no
…

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