January 6, 2010

CCNA / CCNP Home Lab Tutorial: Assembling Your Cisco Home Lab

Filed under: Technology Tips — @ 3:31 am

A CCNA or CCNP candidate who wants to be totally prepared for their exams is going to put together a home lab to practice on. With used Cisco routers and switches more affordable and plentiful then ever before, there’s really no excuse to not have one!

With the many different models available, there is some understandable confusion among future CCNAs and CCNPs about which routers to buy and which ones to avoid. You can take almost any set of Cisco routers and put together a home lab; part of the learning process is taking what equipment you have available and putting together your own lab! For those of you preparing to start your home lab or add to your existing one, this article will list the routers I use in my Cisco pods. You certainly don’t have to have all this equipment, but this will give you some good ideas on how to get started.

The most versatile router you can get for your CCNA / CCNP home lab is a 2520. These routers come with four serial ports, one ethernet port, and one BRI interface for ISDN practice. This mix of interfaces means you can actually use it as a frame relay switch while using the ethernet and BRI ports for routing. (There is no problem with using a lab router as both your frame relay switch and a practice router; for a frame relay switch sample configuration, visit my website!)

My pods consist of five routers and two switches, and three of the five routers are 2520s, due to their versatility. A recent ebay search showed these routers selling for $99 – $125, an outstanding value for the practice you’re going to get.

I also use 2501s in my home labs. These have fewer interfaces, but the combination of two serial interfaces and one ethernet interface allows you to get plenty of practice.

A combination that works very well is using three 2520s; one as my dedicated frame relay switch, one as R1, and another as R2. Add a 2501 as R3, and you can have a frame cloud connecting R1, R2, and R3, a direct serial connection between R1 and R3, an Ethernet segment that includes all three routers, and an ISDN connection between R1 and R2 if you have an ISDN simulator. That combination will allow you to get a tremendous amount of practice for the exams, and you can always sell it when you’re done!

2501s are very affordable, with many in the $50 range on ebay. It’s quite possible to get three 2520s and one 2501 for less than $500 total, and you can get most of that money back if you choose to sell it when you’re done.

With four routers to work with, you’re probably going to get tired of moving that console cable around. An access server (actually a Cisco router, not the white boxes we tend to think of when we hear “server”) will help you out with that. An access server allows you to set up a connection with each of your other routers via an octal cable, which prevents you from moving that console cable around continually. For an example of an access server configuration, just visit my website and look in the “Free Training” section.

Access server prices vary quite a bit; don’t panic if you do an ebay search and see them costing thousands of dollars. You do NOT need an expensive access server for your CCNA / CCNP home lab. 2511s are great routers to get for your access server.

One question I get often from CCNA / CCNP candidates is “What routers should I buy that I can still use when I’m ready to study for the CCNP?” The CCIE lab changes regularly and sometimes drastically when it comes to the equipment you’ll need. During my CCIE lab studies, I found that renting time from online rack rental providers was actually the best way to go. Don’t hesitate when putting your CCNA / CCNP home lab together, wondering what will be acceptable for the CCIE lab a year or so from now. None of us know what’s going to be on that equipment list, so get the CCNA and CCNP first – by building your own Cisco home lab!

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (www.thebryantadvantage.com), home of free CCNA and CCNP tutorials, The Ultimate CCNA Study Package, and Ultimate CCNP Study Packages. Video courses and training, binary and subnetting help, and corporate training are also available. Pass the CCNA exam and CCNP exams with Chris Bryant, CCIE #12933!

For a copy of his FREE ebooks, “How To Pass The CCNA” and “How To Pass The CCNP”, just visit the website to get them!

Blackhole or Fail – Which One Is Better For Your Mail Server?

Filed under: Uncategorized — @ 1:40 am

Very often SPAMMERS take advantage of catch-all email setup on webservers. Every email no matter what the recipients email address is will be caught by the default email account. It is highly recommended not to use catch-all email accounts and to discard SPAM send to non-existing email addresses. SPAM will clog up your SMTP server and consum resources like bandwidth and disk space in mailboxes. In most mail servers and web control panels (like cPanel) the user or admin can decide what will happen to emails with no existing recipient on the server. Refuse to the let emails onto the server and to let the sender’s mail server deal with it (option: “:fail:”) or to accept these incoming messages but then to delete them right away (option: “:blackhole:”.

Our conclusion:

:fail: is the preferred option over :blackhole:.

The :blackhole: option accepts everything sent to the domain mail server and then throws away the email going to a non-existing email account. This option uses the full amount of bandwidth, and also requires that the server be reading and writing messages to disk before they are deleted… multiply this by 1,000 messages a day or so and you can imagine the impact onto your server resources. Imagine your an email address from your domain (a non-existing one) has been spoofed to send out SPAM messages that even carry a virus. Most natural many of these messages will bounce back and hit your mail server. Your web server would have to deal with thousands of attachments at a time. Performance will go down – no matter what.

:fail: stops emails send to invalid recipients from entering the mail server in the first place..Exim will reject each message during the smtp handshake conversation – therefore the actual email message will never make it to your server. It is being refected from entering your system and the sender’s email server has to deal with the stuck message. This option is also the better one for legitimate emails where the sender has actually mis-spelled the recipients email address. He would get a bounce message informing him so that the error can be corrected. Depending on your hardware – a server can handle many more :fails: than it can do :blackholes:.

This article can be published by anyone as long as a live back link to http://www.webhostingresourcekit.com is provided. (this note can be removed as long as a link from the author’s resource box is provided)

Christoph Puetz is a successful small business owner (Net Services USA LLC) and international author.

Guides, Tutorials, and Articles for small businesses – http://www.webhostingresourcekit.com