Connectivity via PPP

In addition to kernel-driven network interfaces (most of which are Ethernet these days), PPP is a common way to access computer networks. PPP itself is actually a transfer protocol between two peers with more features than the Ethernet protocol, allowing for authentication and the negotiation of IP addresses for the calling client. PPP is used in standard InternetService Provider (ISP) modemdial-in scenarios, as well as for DSL (PPPoE or PPP-over-Asynchronous-Transfer-Mode (PPPoA)) connections...

Bootstrapping a new system

When faced with a machine whose hardware does not support regular installation methods - perhaps because the hardware cannot boot off any medium other than the local hard disk - you will need to use an existing system to bootstrap an installation onto the hard disk to be used in the machine. You can bootstrap a new system in two ways, which I will refer to as clean and the dirty way. The dirty approach is dirty because you need to use a screwdriver to move hard disks between machines The clean...

Miscellaneous package tools 5111 debsums

A large number of packages register the files they install in the dpkg database together with their MD5 sums. These data can be used to verify the integrity of the installed files at a later point in time. The debsums tool is made for exactly this purpose, and can optionally augment the database with hashes for packages that did not install them. An APT hook (see chapter 5.4.2) is provided in the package to generate missing hash sums following the installation. It should go without saying that...

The Filesystem Hierarchy Standard FHS

With 15 000 binary packages in the Debian pool at the time of writing, you may wonder how many conflicts had to be resolved between two packages each trying to install a file of the same name. Well, the answer is very few, which may be surprising were it not again for the policy to confine packages to use very specific locations for their files, rather than installing all over the place. Section 9.1.1 of the Debian policy specifies that all installed files and directories must comply with the...

The debhelper suite Overview

Unix is the operating system of scripts and automation. It is therefore unsurprising that most of the steps and functionality needed to create a binary Debian package have been further hidden behind more abstract and simpler interfaces. The most prominent of these interfaces is debhelper, which provides a plethora of small scripts to handle most aspects of packaging in an intuitive and consistent way. The tools are intended for use in the binary-* targets of debian rules. Most of the debhelper...

Debsigs and dpkgsig

While APT 0.6 uses index files to verify package integrity and is thus of little use when the indices are not available, two other tools use signatures attached to the DEB file for the integrity verification dpkg-sig and debsigs. debsigs in package debsigs was written shortly after the release of potato. In the mean time, another programme, dpkg-sig in package dpkg-sig was authored to deal with its shortcomings17. A package signature is similar to the digital signatures as used in e.g. emails,...