Connecting Your Linux Box to the Internet
The Internet service provider business is booming right now. New companies come online each month. Service providers come in all sizes—from large, cross-country providers serving an entire country, to medium-sized, regional providers serving several nearby cities, to small providers serving only a single city.
Finding the larger providers and most medium-sized ones is easy. There are several lists of service providers available; here are a couple I have found useful:
DLIST: A list of Internet service providers that sell direct connections. Most, if not all, of the large national providers are listed here. You can get a copy of this list by sending e-mail with an empty message body to firstname.lastname@example.org. If you have any problems getting this list, send e-mail to email@example.com.
PDIAL: A list of Internet service providers that offer dial-up accounts. The PDIAL list contains many more providers than the DLIST. The additional providers tend to be the small to medium-sized ones. Most of the companies listed will provide dial-up accounts only; however, if you find a provider close to you, call or e-mail them and ask if they sell dedicated connections—some of them might. To receive the PDIAL list, send e-mail to firstname.lastname@example.org with “Send PDIAL” in the body of the note.
Finding the smaller providers that service only your city can be a little trickier. Check your city's computer paper. Check local user groups. Check with local computer stores to see if they know of anyone providing Internet access in the area. You'd be surprised how many consulting firms, out-sourcing companies, and even computer stores are using the unused time on their computer equipment to provide Internet access.
Most providers have an e-mail address you can send mail to for more information; select a few and e-mail them. Describe your site to them and the type of connection you are looking for. For example, if you have an office LAN you want to connect to the Internet, tell them. See what they suggest and how much it will cost.
Now, you have to be careful when it comes to costs. Some providers charge a setup fee. Others require you to sign a six- or twelve-month agreement with them. Some charge only for the Internet feed; you must pay the phone company directly for the dedicated line. Others combine the two charges and you pay the service provider only. Some require you to purchase a CSU/DSU at their site. Others include this charge as part of your setup fee. In the end, you'll have to decide on whether you want the flexibility of a month-to-month lease, or the extra savings of a long-term commitment.
Narrow the possible candidates down to two or three good prospects. Then, ask for references. The best way to check the quality of a service provider's service is to talk with at least three other companies using their service and get their opinions. Ask how long they have had the connection, what they like most, what they like least, how often the connection goes down, and how long it takes to get fixed. Ask for references similar to you in terms of type of connection, number of users, and type of office network.
Maintenance is another issue. Some providers will install the equipment at your site and maintain the equipment remotely; this is a good option for small sites with little experience with the hardware involved. For the more daring, you can install your own equipment at your site. You might have the odd interruption as you learn how things work, but if you don't mind this possibility, the knowledge you gain will be helpful to you later.
You still need to purchase a dedicated line from your site to your service provider's site. Some service providers take care of this for you; others require you to arrange this with the telephone company. Arranging for a dedicated line is not difficult—you could do it yourself. The advantage of having the service provider handle this is you only have one number to call if something goes wrong with the connection. If you are dealing with two companies, each may tell you the problem lies with the other's equipment and will ask you to contact the other first. If you have ever run into this vendor-roulette before, you'll know how frustrating it can be. Neither side wishes to investigate the problem until the other side has investigated things first.
If you have an existing TCP/IP network that you are connecting to the Internet, you may want to set up your Linux box as a firewall between your network and the Internet. This is done to prevent unauthorized users from accessing services you want only your local users to access. See the comp.security.unix FAQ for more information about firewalls. If you plan on connecting dial-in lines to your Linux box, I have some suggestions on the machine size and configuration. These suggestions may not work for every situation, but they will give you a starting point from which to work.
For a small operation with 1-4 dial-in modems, a 486DX33 with 16MB of RAM and a four port serial card would be a good starter system. For a medium sized operation with 4-16 dial-in modems, a 486DX33 with 32MB of RAM and a 16 port serial card might be reasonable configuration to start with. Keep in mind that the CPU speed and amount of memory needed will ultimately depend on what your users will be doing on your system. If they only read news and send e-mail, this might be more than enough. If things start slowing down, add more memory.
For a large operation with 16+ dial-in modems, try two 486DX66s with 16MB each. Put a large hard drive on one machine and NFS mount it on the other machine. With so many modems, you don't want to overburden your Linux box with serial ports. Instead, you can get a terminal server which is a piece of hardware that manages modems. Your modems plug into one end and an Ethernet connection comes out of the other. Another feature of terminal servers is they allow you to attach each modem (or port) to a different Linux box. In this case you have two machines, so assign half to each machine. If your machines are getting overloaded, you can increase memory as before, or you can get a third machine and redistribute the ports accordingly.
Keep in mind that the above systems are only suggestions; there are too many variables involved to suggest that any of the above systems will work in all cases. Your configuration will ultimately depend on how many people use your machine and what tasks they normally perform.
Practical Task Scheduling Deployment
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.
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- Managing Linux Using Puppet
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- Parsing an RSS News Feed with a Bash Script
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- Doing for User Space What We Did for Kernel Space
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