Encryption and Identity Verification using the GNU Privacy Guard (GnuPG)

GnuPG (GNU Privacy Guard) is a tool for creating key-pairs, used for encrypting and signing messages. It therefore provides a means to guarantee a your identity online and protect sensitive information. A key-pair is a mechanism for asymmetric encryption. It consists of a private key and a public key. The public key is shared and is […]

WordPress with FCGID in Apache2.4

FCGID allows PHP to run outside of the Apache process. It also allows the PHP process to run as the user who owns the scripts. This is useful for WordPress as it allows the installation of plugins and themes without the need to enter FTP credentials. To get it running is sometimes tricky as it […]

Creating histograms in gnuplot

I needed to produce a histogram in gnuplot of multiple sets of raw data (i.e. not sumarised). The data in each dataset required binning and displaying on the same plot.

Exim tips

Exim is the standard mail-server of the majority of Linux distributions. Typically, it requires minimal maintenance, but when configuring it, or occasionally when something goes wrong, you have to intervene. Here are a few useful Exim commands: Get the version of Exim: Testing Check the routing of an email address: Note: To ignore a scanner […]


SSH is a highly versatile and secure protocol, allowing remote shell access (through the ssh command) and secure file transfer (through the scp command). SSHFS extends the file transfer concept to provide a filesystem client via FUSE (Filesystem in USErspace). Assuming you already have shell access to a remote machine, it is trivial to mount […]


Here are useful tips I found when dealing with MySQL servers. Repairing crashed tables Sometimes a MySQL utility will report an error such as: You can check the index files using the myisamchk utility, which should show an output similar to: No errors reported In this case, the table is fine, but just marked as […]

Automount and LDAP on Mac OSX

From ‘Leopard’ onwards, OSX supports the standard autofs method for mounting remote filesystems automatically. Specifically, a users home directory may be automounted on logon using attributes provided by the LDAP server. To enable this, the necessary schema entries must be added to the apple.schema file, if this has not already been done. Updating LDAP Additional […]

Samba LDAP configuration

Samba is open-source software which allows a Linux server to provide filesystems to Microsoft Windows clients using the SMB protocol. It may also act as a Primary Domain Controller for a Windows domain allowing users of the Windows clients to authenticate using Linux accounts. Specifically, it also includes support for authenticating against an OpenLDAP server. […]

Mac OSX Authentication against OpenLDAP

Configuring a Mac OSX machine to authenticate users against a Linux-based OpenLDAP server can be slightly tricky. This page is intended to document my experiences. The configuration described here provides simple authentication services and may not be suitable for enterprise level scenarios. Configuring OpenLDAP Disable SASL Mac OSX always attempt to authenticate the LDAP session […]

Using ldapvi to quickly modify LDAP directories

ldapvi is a command-line LDAP directory editor provided through the popular Vi(m) editor. It is provided as a package under Debian: To edit the contents of a local directory server just run This will then prompt for the distinguished name you wish to connect with and the password. For example You can then edit existing […]