The Penguinlinux.com Blog

ldapsearch Command
Purpose
Opens a connection to an LDAP server, binds, and performs a search using the filter filter.

Syntax
ldapsearch [-a ][-A ][-b basedn][-B][-C][-d][-D ][-e ][-f][-F][-G][-h][-i][-k][-K][-l][-L][-m][-M][-n][-N][-o][-O][-p][-P][-q][-R][-s][-t][-T][-U][-v][-V][-w][-y][-Y][-z ][-Z][-9] filter [attributes...]

where basedn equals the base distinguished name for the search, filter equals the LDAP search filter, options equals any other flags, and attributes equals a whitespace–separated list of attributes to retrieve. If no attribute list is specified, all attributes are retrieved.

Note:
basedn is optional if LDAP_BASEDN is set in the environment.
Description
If the ldapsearch command finds one or more entries, the attributes specified by attrs are retrieved and the entries and values are printed to standard output. If no attrs are listed, all attributes are returned.
Continua”LDAP Search flags”

Initial Concepts

Basic
Configuration

Address
Book Entries

TLS Link Encryption

phpLDAPadmin
Web Administrator

Email
Client Settings

Many individuals throughout professional organisations will consider
their list of personal and professional contacts as one of their most
important assets. Similarly at home keeping our contact details of
friends, relatives and professional service providers like physicians
is also equally important, however maintaining that contact list across
several computers can be very time consuming; even frustrating if it is
lost.

Using the Lightweight Directory Access Protocol (LDAP) we can configure
a centrally managed address book that can be shared by all the of
computer workstations throughout the network (for many large
organisations this is a fundamental design concept). A central (or
shared) address book allows easy management of all contact details, it
can be backed up and restored very easily, and it can also be made
available through a secure web interface so it can be accessed remotely
from where ever the user may be.

This chapter will detail the procedures necessary to configure the
OpenLDAP (http://www.openldap.org)
directory service that will provide the basis for our address book and
make it available to our network users. We will also look at populating
the address book and provide security access controls so that only
authenticated users can access the information.

Not all email clients are able to write to the address book (although
reading is fine), this is normally due to the functionality of the
email client and not a problem with the directory service. Therefore,
we will also configure the web server with a web based administration
application which will allow full control of the address book; this
also allows the remote access if needed.

The following list of man pages can provide further information to
assist with configuration or debugging requirements.
Continua”Open Ldap How To”

Managing Entries From the Command Line
The command-line utilities allow you to manipulate the contents of your directory.
They can be useful if you want to write scripts to perform bulk management of
your directory, or to test your Directory Server. For example, you might want to
ensure that it returns the expected information after you have made changes to
access control information.
Continua”Iplanet Command Line LDAP tutorial”

OpenSSL is more than just an open source SSL library implementation. It can be used to create, request, sign, and revoke certificates and can also be used to perform other cryptographic operations such as creating hashes for files, testing SSL connections, and more. This week, we’ll take a look at some of the interesting things that can be done with the openssl command-line program.

To test SSL connections to a mail server, use the openssl command with the s_client parameter:
Continua”Cool things you can do with the openssl command for troubleshooting”

If you make a new entry in fstab it will not auto-mount. Therefore you must reload / refresh the entries. A reboot will do this but that is not a friendly way to do it. A quick way to reload new entries in /etc/fstab (fstab) is to use the mount command:

mount -a

For example this morning, my automatically mounted samba shared folder was giving me an error. It seems that the server lost connectivity to the samba server and I didn’t want to reboot the machine or manually mount it.
Continua”How to reload fstab changes without a reboot.”

found at: http://blog.eikke.com/index.php/ikke/2007/02/21/recovering_a_crashed_lvm2_pv_harddrive

2 weeks ago, due to a power failure, a harddrive in a (UPS protected) server at VTK crashed. Unable to boot the machine, unrecoverable IDE errors,…
The machine was only used as a database server for now (both MySQL and PostgreSQL), and did not make external backups (yet). Yeah I know, stupid, but managing our network isn’t that easy.

Anyway, the harddrive consisted of 3 partitions:

• /boot, ext3
• /, ext3
• an LVM2 PV

Continua”Recovering a crashed LVM2 PV hard drive”

Found at: http://www.ibm.com/developerworks/library/l-lvm2/index.html

Volume management is not new in the -ix world (UNIX®,
AIX, and so forth). And logical volume management (LVM) has been around since
Linux® kernel 2.4v1 and 2.6.9v2. This article reveals the most useful features
of LVM2—a relatively new userspace toolset that provides logical volume
management facilities—and suggests several ways to simplify your system
administration tasks. Based on reader feedback,
the author has updated Listings 10, 14, 15, and 16. -Ed.

Logical volume management (LVM) is a way systems can abstract physical volume
management into a higher-level and usually simpler paradigm. By using LVM, all
physical disks and partitions, no matter what size and how scattered they are, can
be abstracted and viewed as a single storage source. For example, in the
layout of physical-to-logical mapping shown in Figure 1, how could the user create
a filesystem of, say 150GB, since the biggest disk is 80GB large?

Continua”Linux Logical Volume Management”

found at http://codeworks.gnomedia.com/archives/2005/general/lvm_recovery/LVM recovery tale.
Over the weekend I had the worrying experience of losing my LVM settings and potentially all my data… a quick search on the web showed a confusing set of information, much of it for older versions of LVM and therefore rather suspect.

Well, I recovered all my data and it was really quite simple, so I’ve written up what I did in the hope that someone else, in a similar situation, will find it useful. It’s a scary thing, losing the whole hard disk and knowing that, in reality, its all there.
Continua”How to recover from an LVM disaster”

Original Article by etienne

Ok so I’ve finished my new Rails application and it’s now time to deploy, which has turned out to be somewhat more challenging than I thought. I’m deploying to a dedicated host running SuSe 9.3.

Installation check list:

1. Ruby
2. RubyGems
3. Rails
4. Mongrel + Mongrel Cluster
5. Nginx
6. Subversion
7. Capistrano

Continua”Rails Deployment and Installation - Nginx + Mongrel Cluster + Subversion + Capistrano”

We don’t have any type of Netapp setups at work and I am interested in knowing more how people use Netapp devices to provide disk access to linux servers.

I found this great guide. :) and I am saving this for future reference.
Continua”How to setup a Linux server to connect to a NetApp Device”