Rob Golding

My home network has been growing and growing ever since the start. At first, just little linux firewall, and it’s not done yet.

I’ve recently upgraded the my new server, adding another 4GB of RAM to bring the total to 8GB - to give me some more room for playing around. Also, I’ve decided that with all that extra memory I can upgrade to VMware Server 2.0 safely, and all seems to have gone well. Also surprisingly, the load on the machine hasn’t gone up, even with the addition of 2 new virtual machines.

The first new server is an anti-spam gateway for my Microsoft Exchange organisation, and is working flawlessly so far. Second is a Windows Server 2008 machine, which I plan to migrate the domain onto some time in the future. I plan to do some work with the brand new O/S, and see what’s what. I’m sure there will be plenty of material to keep up-to-date with, so keep checking back!

My new laptop, a Dell Studio 1535, has started exhibiting a strange problem as of late; when I hibernate it over night, it resumes early in the morning, waking me up with the fan spinning.

I was preparing to send the thing back to Dell, when it happened one night and I checked out the event logs. It turns out that Windows Update was resuming the machine from hibernate - and then updating itself. After turning this off, I’ve had a good night’s sleep! Also, Windows Defender was scheduled to scan the machine every morning at 2.00am, so that’s been disabled too.

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I hope this post can provide answers to anyone else experiencing a similar issue.

In my last post, I talked about configuring Ubuntu for use with different proxy servers, and something became quite evident. It would have been nice to have a way of aliasing the IPs of those servers, so instead of typing the number out, one could simply type “proxy”, for example.

This can be easily achieved using the hosts file, which is present on both linux and windows operating systems. Here I will discuss how to use the hosts file in Ubuntu linux.

First, you must gain access to the file. It can only be written to as root, so the sudo command must be used, in conjunction with your favourite editor. For example:

sudo gedit /etc/hosts

As you can see, the hosts file is located at /etc/hosts.

To add entries to the hosts file, simply add another line at the end, following the president set by the one or two lines alreay present. The syntax is basic, and consists of the IP to be aliased, then the name that you would like to alias it with. For example, the proxy in my last post could be entered as follows:

128.243.253.119    proxy

As it happens, this is actually a surprisingly effective method of blocking malicious websites, and even adverts. Quite simply, any domain that you would not like your browser to access, can be added to the hosts file with an IP of 127.0.0.1. This is the IP address for the local machine you are currently working on. For a huge list of such websites, check out www.someonewhocares.org/hosts. Simply copy and paste the file on that site into your hosts file, and you’re set. It should be noted that this will work on windows, Mac or linux. On Windows XP/Vista the hosts file is located in:

C:\Windows\system32\drivers\etc\hosts

Obviously if your Windows installation is on a different drive, simply replace C: with the relevant letter.

I have recently enrolled on a Computer Science course at The University of Nottingham, and as such have had to make sure my machines correctly use their proxy server for web access. This post outlines the process of configuring Ubuntu for exactly that purpose - and could be applied to any network with a similar layout.

Network Proxy

First and foremost, Ubuntu has a setting in gnome for the Network Proxy, which should set gnome’s proxy - but I can’t see as it affects anything at all - still, better to be safe than sorry.

At Nottingham University, the recommended configuration is a proxy auto-configuration script (proxy.pac) which is downloaded by the client and parsed to configure the appropriate proxy server. In this case, it is located at http://wwwcache.nottingham.ac.uk/proxy.pac. This URL is entered into the correct field of the gnome Network Proxy settings dialogue.

Terminal Proxy

Secondly, the terminal has a proxy configuration option, so that programs that run inside the terminal making HTTP requests can access the internet - namely wget and aptitude. This is slightly more difficult to configure than the previous, and is achieved like so:

The terminal proxy is set using a variable called http_proxy, which is set using the export command, i.e.

export “http_proxy=http://proxy_server_ip:port”

In this case, the proxy server’s IP and port for the SNS (Student Network Service) is 128.243.253.119:8080.

This change can be made permanent by editing /etc/bash.bashrc, and adding the above line to the end of the file. Otherwise, the change is only effective in the terminal window currently open by the user, and disappears when it is closed.

Synaptic

Lastly, Synaptic Package Manager must have the proxy set, in order to update your installation using the in-built Update Manager or Synaptic GUI. This is done by opening Synaptic, and choosing Settings, Preferences, and setting the above proxy information using the Network tab. Unfortunately Synaptic cannot read auto-configuration scripts, so the IP and port must be manually entered here.

Obviously once all this is done, Firefox must be configured to use the correct proxy - but I trust you know how to do that! This turns out to be quite a pain, so I’ll be looking at ways to do this in one fell swoop. If anyone has any suggestions, then please let me know.

Note: These changes can be made much less painful by adding an entry to the hosts file for each of the proxy IPs you need to configure - so you only need to type the word proxy for example, instead of the entire IP. I will document this process shortly in a separate post.

As time goes on I seem to be accumulating more and more machines - whether they be physical or virtual - which causes somewhat of a problem with my bookmarks. I use my bookmarks as a sort of knowledgebase, with solutions to problems I have encountered in the past for example.

The solution to this dillema: Foxmarks. I’ve had this addon for a long time now - since it was just a simple little bookmarks backup application - so I’m really impressed with how it’s turned out. Basically, Foxmarks syncronises your bookmarks with their server, so that you can access your bookmarks from any machine with firefox installed. It also functions as a backup if your profile goes bad.

Recently I’ve started at university, so I’m using my laptop as my primary machine nowadays, along with a firefox profile on the Computer Science machines. I’ve also got a few virtual machines on my laptop with firefox, so the amount of profiles is getting larger by the day. This is where foxmarks really comes into its own, keeping my bookmarks current between all my installations.

I have recently upgraded my home server, shelling out on a new Core 2 Duo CPU and 4GB of RAM for the machine. Having this much RAM means that in order to use it, I had to install a 64-bit O/S. I chose Ubuntu Server 8.04 - and VMware Server to host my virtual machines. I have put together a Word Document with some notes on the issues and tips I came accros on the way, which could prove invaluable to anyone taking the same approach as me. One of the main sources for my research and tinkering ideas was a post on the VMware Community forums - http://communities.vmware.com/thread/146002 - linked to inside the Word Document.

This post made extremely interesting and informative reading – if one can understand the material in that post, then a lot of load issues can be easily resolved– especially IOWait issues (my particular concern). My issue turned out to be a mixture of the settings above, and Postfix misbehaving.

See the word document here.

Update: Advice followed, PDF available here.