Posts tagged howto

HOWTO: SSH config on Debian/Ubuntu

1
February 18, 2010
by Kura in , , ,

Today I finally got round to setting up my local user ssh config on my new work laptop and figured I'd do a quick write up on it and it's uses.

You can create a configuration file in your home directory that will override the options set in your machine-wide config.

Your configuration files

Your local config can be found/created in:

~/.ssh/config

And your machine-wide configuration is in:

/etc/ssh/ssh_config

Rather than editing my ssh config across my whole machine I'm doing it for my local user specifically.

Reading the man page for ssh_config will give you a full list of available options, More >

HOWTO: Guest Virtual Machine disk extend online with Debian/Ubuntu, LVM2 and VMWare ESX

10
February 16, 2010
by Kura in , , ,

Over the last two days I've had the interesting task of online some VMs from clones and increasing their disk space to accommodate a mass of user uploaded content. I've done this before but never actually with an Logical Volume Management (LVM) disk.

My first approach, like a fool, was to clone the VM from source and boot it from a remotely mounted GParted ISO, this didn't actually go as expected and I was unable to add it to the LVM, I found a nice guide online and consulted a colleague because I knew he'd done something similar recently. After the first successful size increase I realised I More >

More nginx proxy_cache optimizations and nginx load balancing

4
February 14, 2010
by Kura in , , , ,

This is yet another follow up to post to several previous posts about using nginx as a reverse proxy with caching. It is actually a direct addition to my post from a week or so ago which outlined how to actually using nginx's proxy caching feature which can be read here -- http://syslog.tv/2010/02/07/nginx-proxy_cache-and-explained-benchmarked/.

Even more changes?

Yes, even more changes, these are basic changes that are there to improve the caching capabilities and also implement load balancing.

Cache changes

The first set of changes are in the main nginx configuration More >

HOWTO: DomainKeys with Postfix on Debian/Ubuntu

6
February 12, 2010
by Kura in , , , ,

I have written a much newer, clearer and better article on DomainKeys signing email here. <

About

This guide is a sister to another guide I wrote a while back about how to use DomainKeys Identified Mail (DKIM) with Postfix on Debian, which can be read here - http://syslog.tv/2010/01/11/dkim-on-debian-with-postfix/.

DomainKeys is an older implementation than DKIM, DKIM is a merge of DomainKeys and Identified Mail. Both DomainKeys and DKIM are used so having both configured is a good idea.

Getting started

Lets start off by installing the dk-filter

sudo su; apt-get install dk-filter

Once More >

HOWTO: Using SPF to validate outgoing mail

0
February 11, 2010
by Kura in ,

You can get a basic overview on what SPF is, what it's for and it's more advanced usages here - http://www.openspf.org/

This article is to give only a basic insight in to how you can use an SPF record to valid mail from your servers.

The DNS

SPF records work from your DNS, it's really simple. Technically there is a DNS type defined for SPF records as of RFC 4408, but since not all servers recognise this type it also works in the TXT type.

A simple usage of SPF is

v=spf1 a mx -all

Imagine this exists on this domain, syslog.tv. This spf record would mean that ALL AN  and MX servers listed in More >

HOWTO: IPTables on Debian/Ubuntu

0
February 11, 2010
by Kura in , ,
Installation

Simple, if it's not installed already then run the following commands

sudo su

apt-get update && apt-get install iptables

/etc/init.d/iptables start

The safest and best way of configuring iptables, in my opinion, is to have two files. The first is a temporary/test set that you will save to first, the second is the actual rule set that will be loaded to iptables.

Configuration

So, first we'll create an empty temp rules file

touch /etc/iptables.temp.rules

Add some simple rules to it

*filter

# Allows all loopback traffic and drop all traffic to 127/8 that doesn't use lo -A INPUT -i More >

nginx, proxy_cache and reverse proxying explained & benchmarked

3
February 7, 2010
by Kura in , , , , ,
The beginning

Where to begin? nginx would be a good start I suppose. It's far easier and makes much for sense for you to actually read about nginx from it's own website - http://nginx.org/en/ - but just to give a simple explanation too; `nginx is king of static content HTTP servers.`

Anyone that has dealt with Apache on medium to high traffic websites will know that Apache is bit of a `wheezy, old geezer` when it comes to content serving using it's mpm-worker (threaded). Very often high traffic will cause server load to go through the roof but for serving dynamic content, there really is no More >

Coming soon… Ubuntu + Nagios2 + Server clusters

0
February 3, 2010
by Kura in , , ,

Well, title says it all really, an Ubuntu howto for Nagios2, the monster of all monitoring software. Watch this space.

HOWTO: Debian – Apache 2 SSL on multiple virtual hosts

4
January 15, 2010
by Kura in , ,

Figured I'd write this one up quickly as it proved to annoy the hell out of me at 4:30am this morning getting it working on a live server.

Apache 2 can serve SSL content to multiple vhosts on your setup, provided they use different IP addresses, this post will give you a quick run down on how to do it.

First up we need to actually add the new IP to the machine in /etc/network/interfaces.

auto eth0

iface eth0 inet static

address 10.1.1.7

netmask 255.255.255.0

gateway 10.1.1.1

auto eth0:1

iface eth0:1 inet static

address 10.1.1.8

netmask 255.255.255.0

Replace my IPs with your own.

Restart More >

HOWTO: Debian server security

1
January 14, 2010
by Kura in , , , , , ,

Server security is something I've always tried to keep myself up-to-date on. I have at least a dozen RSS feeds that I read daily to learn about the latest flaws, holes releases etc. That being said I am by no means an "expert", I've learned what I've needed to learn over time. I like to think that over the years I've gained enough knowledge to almost completely secure servers with all the programs installed that I generally use.

The aim of this article is to introduce you to some of the programs I use for security and some config changes that can be made to other programs to make them more More >

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