Linux Means Business: A Case Study of Pakistan On-Line
Pakistan On-Line (POL), http://www.pol.com.pk/, is an Internet Service Provider (ISP) operating in major cities of Pakistan. All of its Points of Presence (POPs) are operating on Slackware Linux, with some minor setup variations on each site. The ISP's local backbone uses fiber optic cable from a local telecom company, Pakistan Telecommunication Company Limited. Cisco routers are used at each POP to manage this backbone. POL has multiple links to the Internet and uses routing algorithms to manage traffic.
Other than Internet access services, the company also provides services for network design, installation, web development and hosting, domain name registration, etc. For remote-access services, POL uses Cisco and Xyplex access services at major POPs and Linux with Rocketport cards at smaller sites. Linux is used on HP Netservers and Compaq machines to provide Internet services like SMTP, POP, DNS, WWW, FTP, Proxy, etc. User authentication is done through a RADIUS server running on a Linux machine. User accounting and billing are done through RADIUS for Cisco remote access servers and Syslogd where Xyplex remote access servers are used. The accounting and billing process is also carried out on Linux through custom software developed in C.
Choosing a network operating system for Internet operations is a very important decision. You need to be certain about the stability of your entire system, as the setup has to serve so many clients around the clock. Nobody can afford a service outage, even for a few minutes. Since we planned to use Intel-based servers, we had to choose between a Windows NT server and Linux. The most important factor was not the cost of the operating system, but the stability of the ISP facility. Our criteria for selecting an operating system depended on the following factors.
Previous experience: we had a very good experience with Linux, as we had already built large Linux-based networks. Some of these are being utililized in a similar environment, and some in educational institutions.
Stability: Linux was well-tested for stability by our staff in operations of different nature for many years. We were quite confident that it would not give us any problems in our operations.
Cost: although the cost of the operating system itself is not a major factor, when you add the other utilities and software required for an ISP, it is something to be considered. Not only is Linux free of cost, but you can also find all the required software for an ISP entirely free on the Internet. This includes mail servers, web servers, FTP and DNS servers that come bundled with Linux, making it a complete Internet solution. Additionally, if any of the available software does not serve a particular purpose, you can easily try one of the many available alternatives. For example, if you feel Sendmail is too complex to administer and have a mixture of UUCP and SMTP services, you can use Smail instead, which is quite easy to administer and a very useful UUCP-to-SMTP gateway.
Ease of administration, customization and support on the Internet is another major issue. If you want support for commercial software, you have to pay someone on a regular basis. Linux is perhaps the only product for which you can get on-line help around the clock from so many experts all over the world without spending a single penny. It is quite fun to go to an IRC channel and join the discussion.
Although commercial operating system vendors are trying to bundle everything with their products, it is simply impossible for any of these to provide a number of utilities comparable to those available on Linux. People have built many tools and utilities for ISP operations in particular. For example, you can find many tools for analyzing web traffic logs, monitor the utilization of your Internet bandwidth, manage user accounts, check security holes, etc.
There is simply no match for the mail servers available on Linux. Using Sendmail, qmail or Smail, you can do anything you wish. If you want to go for ease of use in a mixed UUCP and SMTP environment, use Smail 3.2. If you want a complete, thoroughly tested, comprehensive solution, use Sendmail. If you just want to give support for SMTP, IMAP, virtual domains, etc., use qmail and so on. You are free to make your choices depending upon your environment.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
Free to Linux Journal readers.Register Now!
- Paranoid Penguin - Building a Secure Squid Web Proxy, Part IV
- SUSE LLC's SUSE Manager
- Google's SwiftShader Released
- Managing Linux Using Puppet
- My +1 Sword of Productivity
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- Non-Linux FOSS: Caffeine!
- SourceClear Open
- SuperTuxKart 0.9.2 Released
- Parsing an RSS News Feed with a Bash Script
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide