HYPERAXE

There are times wherein you would want to have multiple IP addresses for a single machine but just don’t have the resources or a justified need to add additional network interfaces. Let’s say you just want to be able to configure an Apache Web Server and Mail Server (Sendmail, Postfix,etc.) to listen on separate IP addresses. You just then need to provide a virtual IP address to your existing network interface to be able to configure your web server and mail server to listen on differen IP addresses.

Here’s a simple way to do it.

In these examples, we are just going to use IP addresses in the reserved IP range 192.168.0.1. Reserved IP addresses simply means that these are not valid IP addresses in the Internet but rather reserved for use internally or in other words inside a LAN.

For a machine with just a single network interface you would have eth0 as your network interface number. So to add an additional IP or virtual IP for this network interface we just need to issue the command:

ifconfig eth0:0 192.168.10.2 netmask 255.255.255.0 up

Notice that we used eth0:0 as the network interface number for our virtual IP. You can actually use any number after eth0: such as eth0:1,eth0:2,etc. I usually start my virtual network interface number with 0 ( eth0:0 ) but you can start with 1 if you want to. It doesn’t really matter but you just have to make sure that your network interface number and virtual IP addresses are unique. Network problems would surely occur if your settings aren’t unique.

Another way of doing this is by creating a file named /etc/sysconfig/network-scripts/ifcfg-eth0:0 and adding these lines to the said file (this is on a RedHat/Fedora/CentOS Linux machine):

DEVICE=eth0:0
ONBOOT=yes
BOOTPROTO=static
BROADCAST=192.168.10.255
IPADDR=192.168.10.2
NETMASK=255.255.255.0
NETWORK=192.168.10.0
ONBOOT=yes

Then restart your network services by executing:

$> /etc/rc.d/init.d/network restart

This approach would then make sure that your virtual IP address would be configured even after a restart or reboot.

Well that’s it. You can now configure your services to listen to your new virtual IP addresses.

[tags] Virtual IP, Linux Virtual IP, Linux Networking, CentOS, Fedora, RedHat, Linux Virtual IP Addressing, IP Addressing, IP Address[/tags]

Today, my VPS was finally upgraded to a much higher plan. I requested the upgrade a couple of days ago, but sad to say there weren’t any available resources for the upgrade so I had to wait a while. Well, this morning I was so glad the the upgrade was finally done.

The reason I decided to have an upgrade is I wanted to add integrate Tomcat with Apache and a VPS with just 128MB of RAM isn’t enough. Since my VPS also hosts a couple of PHP website, MySQL, and mail and DNS services, adding Tomcat on top of it just pushes my VPS to its limits and the allocated resources are all consumed until I hit the wall. So I upgraded to the next VPS plan which gives me 256MB of RAM and additional CPU resources. I know that this isn’t much but for just a simple server I’ll used for java pet projects I think it would be enough.

Well, cost-wise I think adding a couple of hundred bucks would definitely be worth every penny considering that I’ll have my own Java Application Server to play with and improve my competence with my chosen field of work.

[tags]Tomcat, Java, VPS, VPS upgrade, Java Application Server, Java Application, VPS RAM, RAM, VPS Memory, Java Website[/tags]

Today, I decided to add some WordPress plugins to my blog. I did a bit of research on what plugins would be useful for me and found the following:

• SimpleTags - This plugin allows me to create a list of relative Technorati tags at the bottom of my posts. I think this would somehow increase my blog’s visibility at Technorati and allow more relative searches to point to my blog.
• Fuzzy Recent Posts - I’ve always wanted something like this in my blog which is some sort of an additional item in the sidebars that shows my most recent posts. I could’ve coded this myself but didn’t that much time lately so I decided to look for a ready made plugin and this is what I found.
• Fedburner Feed Replacement - This plugin integrates my blog to my Feedburner account by forwarding my blog feeds while creating a randomized feed for Feedburner to pull from. At least now, my blog feed would be updated on Feedburner and allows more efficient interaction with different feed readers.

That’s all for now. There are still a lot of WordPress plugins out there, but for today, I think I had enough.

[tags]WordPress, WordPress Plugins, SimpleTags, Fuzzy Recent Posts, Feedburner, Feedburner Feed Replacement, Blog Tools, Blog Plugins, Increase Traffic, Feed Readers[/tags]

Opera Software previously released the new Opera Mini 2.0 mobile browser. This newer version of the Opera Mini offers a much slicker interface, additional settings options, as well as faster download time web/wap sites.

Downloading it to my Nokia 6230i was very easy. I just pointed my mobile phone’s built-in browser to http://mini.opera.com and then clicked on the link to download the application. After the installer was downloaded, I was prompted to install the application and then after accepting the request, I now have the Opera Mini 2.0 on my phone.

This little piece of mobile application is very useful for those on the move. You can now view websites with ease wherever you are as long as you have your mobile device with you and an available GPRS/3G network coverage. Opera also did a great job in optimizing the download speed and the amount of data transmission through some sort of packet compression. The pages are also optimized for better viewing on the mobile device’s small screen. You can of course never compare it with what you see on desktops and notebooks screens, but considering that the text and images are shown quite decently, then I think this would suffice for most mobile users.

So for the power mobile users out there, give the Opera Mini 2.0 a ride and you’ll enjoy the browsing mobility it offers. And besides, you got nothing to lose since it’s FREE!

[tags] Opera, Opera Mini, GPRS, 3G, Mobility, Mobile Phone, Cellphone, MIDP, J2ME, Java, Mobile Software, Mobile Tools, Browser, Mobile Browser, Free Downloads, Free, GSM, Cellphone[/tags]

This is another great feat for us Filipinos. I can’t help but feel proud to be a Filipino when I learned that Heracleo “Leo” Oracion made it to the top of the 8,848-meter (29,035-foot) Mount Everest at 3:30 p.m. Wednesday in Nepal (5:30 p.m. in Manila) and Erwin “Pastour” Emata reached the summit at 5:34 a.m. (7:34 a.m. in Manila). The whole nation is now celebrating another great achievement in our history books.

“The Philippine eagle has landed at the summit of Everest”, said Oracion when he reached the summit of the highest mountain on earth as stated by Art Valdez, leader of the First Philippine Mount Everest Expedition Team. Oracion couldn’t have said it much better, and he has proven that we got what it takes to soar high, and considering that Emata also reached the summit doubles up the truth behind such statement.

Considering that the highest mountain in our country is lower than 3,000 meters and we have no winter season here to make us adapt to climbing conditions for Mt. Everest, it could be well said that what the First Philippine Mount Everest Expedition tried to achieve is one ambitious goal. Now that this goal had been achieved, it’s no more of an ambition but a great achievement for all of us Filipinos.

I do believe that we’re one race that can easily adapt to any condition and are survivors by nature. This may well be the reason that even Mt. Everest couldn’t bring us down. To the First Philippine Mount Everest Expedition Team, congratulations and the whole Filipino nation salutes you and thank you for making us proud.

[tags]Filipinos, Filipino Achievements, Mt. Everest, Mountain Climbing, Proud to be Filipino, Philippines[/tags]

Installing a Squid Proxy Server on a CentOS Linux machine is pretty easy. Thanks to the command “yum” which allows you to download the needed packages for the said software. You just have to make sure that your Linux box is connected to the Internet since the packages are downloaded from remote repositories. In the first place, what’s the point of installing a proxy server on a machine that’s not connected to the Internet.

This tutorial or a mini-howto only shows the most basic installation. It’s just some sort of an out of the box installation if you prefer it that way. Oftentimes, applications or services downloaded through yum usually works with its default settings, but in the case of the Squid Proxy Server you have to tweak a few configurations to make things work.

Let’s start.

1. First of all, login to your machine as the root user and then issue the following command:

$> yum install squid

2. Then just follow the instructions and select “Yes” or press “Y” when asked if you want to continue with the installation.

3. After the needed packages have been downloaded and installed don’t try to start the Squid Proxy Server just yet. You would only receive some sort of errors regarding some lines of the config file. So before starting anything edit the file /etc/squid/squid.conf by doing the following:

Find the line visible_hostname and then give it a value. Usually this is the hostname of your PC including the domain name:

visible_hostname squidproxy.domain.com

By default the Squid Proxy Server restricts serving proxy requests from other hosts so you have to add your network to the access list. If for example your LAN network is defined as 192.168.120.0/255.255.255.255, add the following lines:

acl mynetwork src 192.168.120.0/255.255.255.255

http_access allow mynetwork

4. Now you can start the Squid Proxy Server using the command:

/etc/rc.d/init.d/squid start

That’s it, you now have a working Squid Proxy Server. Please remember, this is just the most basic configuration for running it. There are a lot of other things you can do with this proxy server and also some ways to improve the performance which I didn’t cover here. You can visit the Squid Proxy Server website at http://www.squid-cache.org for more information.

Happy proxying!

[tags]Squid Proxy Server, CentOS, Linux, Networking[/tags]