Category Archives: Linux

BIND DNSSEC Signing

DNSSEC Signing w/ BIND

To solve the chicken-or-egg problem for DNSSEC from the other side, let’s use an authoritative DNS server (BIND) for signing DNS zones. This tutorial describes how to generate the keys and configure the “Berkeley Internet Name Domain” (BIND) server in order to automatically sign zones. I am not explaining many details of DNSSEC at all, but only the configuration and verification steps for a concrete BIND server.

It is really easy to tell BIND to do the inline signing. With this option enabled, the admin can still configure the static database for his zone files without any relation to DNSSEC. Everything with signing and maintaining is fully done by BIND without any user interaction. Great.

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Basic BIND Installation - featured image

Basic BIND Installation

This is a basic tutorial on how to install BIND, the Berkeley Internet Name Domain server, on a Ubuntu server in order to run it as an authoritative DNS server. It differs from other tutorials because I am using three servers (one as a hidden primary and two slaves as the public accessible ones), as well as some security such as denying recursive lookups and public zone transfers, as well as using TSIG for authenticating internal zone transfers. That is, this post is not an absolute beginner’s guide.

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ownCloud Data Directory

ownCloud Data Directory

I initially stored my ownCloud data on an external NTFS hard disk. (Yes, this was not a good idea at all.) After some time now I wanted to move the files to a bigger ext4 drive on the same machine. Unluckily there are many posts and articles that are really irritating on the Internet, such as: 1, 2, 3, 4, 5. At least I found some promising hints at the official GitHub forums (this and that) and gave it a try:

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ntopng Installation featured image

ntopng Installation

Some time ago I published a post introducing ntopng as an out-of-the-box network monitoring tool. I am running it on a Knoppix live Linux notebook with two network cards. However, I have a few customers that wanted a persistent installation of ntopng in their  environment. So this is a step-by-step tutorial on how to install ntopng on a Ubuntu server with at least two NICs.

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Roundcube

Roundcube Installation Guide

Roundcube is an email webclient which is easy and intuitive to use. I am using it for my private mails, connecting via IMAP and SMTP to my hoster. One of the great advantages is the “flag” option which is synchronized via IMAP to my Apple devices.

Following is a step-by-step installation guide for Roundcube plus an update scenario. It is a kind of “memo for myself”, but hopefully, others can use it as well.

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ownCloud2

Yet another ownCloud Installation Guide

If you want to use you own ownCloud installation, you can find several documentation on the Internet on how to set up this server, e.g. the official ownCloud documentation, or installation guides such as this or that or here. But none of these page alone provided enough information for installing a secure server completely from the beginning.

So here comes my step-by-step guide which surely won’t be complete, too. 😉 However, hopefully it will help other people while searching for their way to install ownCloud. Additionally I am showing how to upgrade an ownCloud server.

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ntopng featured image

Out of the Box Network Analyzer “ntopng”

Some time ago I installed a new firewall at the customer’s site. Meanwhile the customer was interested in the flows that are traversing through the firewall right now. Oh. Good question. Of course it is easy to filter through log messages of firewalls, but theses logs are only for finished sessions. Yes, there are “session browsers” or the like on all firewalls, but they are not nice and handy to analyze the sessions in real-time.

The solution was to bring a network analyzer on a mirror port near to the firewall. I decided to use ntopng running on the live Linux distribution Knoppix. Great choice! An old notebook with two network adapters fits perfectly. A handful commands and you’re done:

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Basic IPv6 Messages - Featured Image

Basic IPv6 Messages: Wireshark Capture

When explaining IPv6 I am always showing a few Wireshark screenshots to give a feeling on how IPv6 looks like. Basically the stateless autoconfiguration feature (SLAAC), DHCPv6, Neighbor Discovery, and a simple ping should be seen/understood by any network administrator before using the new protocol.

Therefore I captured the basic IPv6 autoconfiguration with a Knoppix Linux behind a Telekom Speedport router (German ISP, dual-stack) and publish this capture file here. I am using this capture to explain the basic IPv6 features.

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Log Parsing Commands 3

Logfile Parsing

While parsing logfiles on a Linux machine, several commands are useful in order to get the appropriate results, e.g., searching for concrete events in firewall logs.

In this post, I list a few standard parsing commands such as grep, sort, uniq, or wc. Furthermore, I present a few examples of these small tools. However, it’s all about try and error when building large command pipes. 😉

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syslog-ng

Basic syslog-ng Installation

This post shows a guideline for a basic installation of the open source syslog-ng daemon in order to store syslog messages from various devices in a separate file for each device.

I am using such an installation for my routers, firewalls, etc., to have an archive with all of its messages. Later on, I can grep through these logfiles and search for specific events. Of course it does not provide any built-in filter or correlation features – it is obviously not a SIEM. However, as a first step, I think it’s better than nothing. 😉

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Palo Alto GlobalProtect for Linux

Palo Alto GlobalProtect for Linux with vpnc

This is a tutorial on how to configure the GlobalProtect Gateway on a Palo Alto firewall in order to connect to it from a Linux computer with vpnc.

Short version: Enable IPsec and X-Auth on the Gateway and define a Group Name and Group Password. With this two values (and the gateway address), add a new VPN profile within vpnc on the Linux machine. Login with the already existing credentials.

Long version with screenshots comes here:

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jw-vm01.cfg-localhost-memory-ms-l2

MRTG/Routers2: Adding a Linux Host

This post describes how to add a Linux machine to the MRTG/Routers2 monitoring server. First, the host must be able to process SNMP requests. Then, a *.cfg file for MRTG/Routers2 is created by running the “cfgmaker” tool with a host-template. Since a few values are wrong in the cfgmaker file, I also explain how to correct them. Finally, I am adding the mrtg-ping-probe lines to the configuration.

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routers2

MRTG with RRDtool and Routers2 – Installation from Scratch

I always wanted to monitor my private network with an open source tool. Since I knew some nice statistics, e.g. from the DE-CIX (printed with RRDtool) or from the Uni-Gießen (generated with MRTG), I had the idea of installing such a system by myself. Luckily I found a book from Steve Shipway, called “Using MRTG with RRDtool and Routers2“, which actually disappointed me because it did not offer a complete installation guide but mainly further information about fine-tuning the appropriate tools.

Therefore, I want to show a complete step-by-step installation of all the needed tools in order to monitor a network with MRTG, RRDtool and Routers2.  “From scratch” means that there are no prerequisite to this installation guide except a plain Linux server (in my case a Ubuntu Linux) such as presented here. Okay, let’s go: Continue reading MRTG with RRDtool and Routers2 – Installation from Scratch

A really tiny vi tutorial featured image

A Really Tiny “vi” Tutorial

A few days ago I needed to use vi for a simple change in a single file. However, I am not using vi in normal situations since I prefer the usage of “nano“. Since I only needed to edit a few lines, all the command references I found on the Internet were much to overwhelmed, so I decided to write a really tiny vi tutorial which only shows the commands in order to edit a file and to close it afterwards. Here we go:

Open the file with vi textfile.

Go into the edit mode with “i” and edit the text. When you are finished, hit the Esc key to leave the edit mode. Type a colon followed by an “x” (appears at the bottom line) to quit vi with saving the changes. Thats it. Here is the sequence at a glance:

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New Linux Server Program Installation

New Linux Server Program Installation

Okay, I know this is no new stuff for many of you but I need it from time to time and I am always searching for this. It is simply a list of the programs I need after a new Linux server installation (used with Ubuntu server) as well as some further hints for the installation process. So, after the initial installation the following steps can be done:

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