by: Chris Bryant, CCIE #12933

DNS behaviors of a Cisco router are important topics for both the CCNA exam and real-world production networks, and you probably didn't know there were so many DNS details before you began studying for the exam! In this tutorial, we'll look at the ip name-server command and its proper usage.

When a command is mistyped on a Cisco router, the default behavior of the router is to attempt to resolve it via DNS. First, the router looks for an IP Host table on the local router to perform this resolution – that’s what the “translating” word in the output is referring to. If there’s no IP Host table or the IP Host table doesn’t contain an entry for what you typed, the router will send a broadcast in an attempt to resolve this name through a remote DNS server. To prevent this broadcast, enter the global command no ip domain-lookup. Of course, to use DNS to resolve hostnames, ip domain-lookup would have to be reenabled if it’s been turned off.

R2#contin

Translating "contin"...domain server (255.255.255.255)

% Unknown command or computer name, or unable to find computer address

A command is mistyped as “contin”. The Cisco router’s default behavior is to resolve this entry locally via an IP Host table, which isn't present on the router. A broadcast is then sent out to find a DNS server to perform the name resolution. The DNS lookup attempt must time out before the configuration can continue.

R2#conf t

R2(config)#no ip domain-lookup

R2#contin

Translating "contin"

% Unknown command or computer name, or unable to find computer address

With “no ip domain-lookup” configured, the router doesn’t attempt to find a remote DNS server. It sees there is no local resolution configured and almost immediately sends a message to the console that the name can’t be resolved.

R2#conf t

R2(config)#ip domain-lookup

R2(config)#ip name-server 10.1.1.1

R2#contin

Translating "contin"...domain server (10.1.1.1)

A DNS server is installed on the network with the IP address 10.1.1.1. DNS lookup is reenabled with the command ip domain-lookup, and the IP address of the DNS server is specified with the ip name-server command.

It's just that easy to tell a Cisco router exactly where the DNS server is!


About The Author
Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (thebryantadvantage.com), home of free CCNA and CCNP tutorials, The Ultimate CCNA Study Package, and Ultimate CCNP Study Packages.
You can also join his RSS feed and visit his blog, which is updated several times daily with new Cisco certification articles, free tutorials, and daily CCNA / CCNP exam questions! Details are on the website.
For a FREE copy of his latest e-books, “How To Pass The CCNA” and “How To Pass The CCNP”, visit the website and download your free copies. You can also get FREE CCNA and CCNP exam questions every day! Get your CCNA study guide from The Bryant Advantage!
chris@thebryantadvantage.com




------------------------------------------------------------------------
More posting about computer tutorial category :

• telkom logo with coreldraw
• playing arround with text
• pearl lexicon
• back road loophole
• record voice using microphone
• ardour
• cakewalk syntheizers
• cakewalk announces sonar
• apple pro tips from eps to pdf
• inkscape
  

Labels: computer software, computer tutorial, software, software tutorial

by: Rock Ren
Pearls are among the most the most exquisite of the gemstones. Pearl jewelry is considered classically beautiful, and a demonstration of the wearer’s fine taste. Pearls have been used for many purposes, including jewelry, for thousands of years and have become an entire industry, complete with a unique vocabulary.

Pearl

A pearl is a small, round object created by certain species of mollusks. The pearls are created overtime by the mollusk depositing layers of calcium carbonate over an irritating intrusion in its shell. Pearls have a tremendous variety of sizes, shapes, and luster as well as their origination location. These factors all play a role in determining the value of the gemstone.

Freshwater Pearl

A freshwater pearl is created naturally, or most often cultivated, in freshwater mussels in lakes, streams, or ponds. The majority of freshwater pearls are produced in China, and those pearls have a distinctive rainbow luster.

Saltwater Pearl

Saltwater pearls are found in the ocean, generally in small protected coves or bays. Saltwater pearls tend to be the most expensive of the collection as they are more often naturally forming. Saltwater pearls appear in a variety of colors, including white, ivory, pink, yellow, purple, blue, and black. Perfectly round, black saltwater pearls are considered the most valuable.

Cultivated Pearl

When farmers deliberately create pearls by inserting grit into a mollusk, they have cultivated those gemstones. Cultivating pearls began in Japan in the very late 1800s, and the process is now responsible for almost all pearls used in jewelry today. Cultivation includes implanting a small piece of polished abalone into a mussel along with an irritant to stimulate production. The pearl takes roughly three years to cultivate, and when it is removed, the mussel is often used again to create another pearl.

Cultivated pearls are considered less valuable than natural pearls, but to determine the difference, an x-ray machine must be used by a jeweler. Cultivated pearls will have a perfect sphere at the center, while naturally occurring pearls will have an irregular center.

Imitation Pearl

Imitation pearls are often used in jewelry, but are not naturally created or cultivated. They are manufactured. Imitation pearls are easy to identify as they are made of difference substances such as glass, abalone, mother-of-pearl, or conch shells. The weight and smoothness of imitation pearls is very dissimilar from real pearls, and the imitation is the least expensive pearl available.

Pearl Jewelry

Overtime, jewelers have used pearls in a variety of ways. Rings, bracelets, brooches, earrings and necklaces use different styles of pearls, and the resulting creations are considered elegant. Necklaces enjoy the greatest range of styles, and this assortment has resulted in very specific names.

Collar – A collar of pearls sits directly at the throat and is generally comprised of multiple strands.

Choker- A choker sits slightly lower than the collar, at the base of a woman’s throat.

Princess – A princess drapes to or slightly below the collar bones.

Matinee of Pearls – The matinee comes slightly lower than the princess, ending on a woman’s chest.

Opera – An opera reaches past the bosom to the sternum.

Pearl Rope – The pearl rope is a length of pearls exceeding the opera.

About The Author
Rock Ren is the owner of xaxe.com. You can find more information at http://www.xaxe.com/


------------------------------------------------------------------------
More posting about computer tutorial category :

• telkom logo with coreldraw
• playing arround with text
• pearl lexicon
• back road loophole
• record voice using microphone
• ardour
• cakewalk syntheizers
• cakewalk announces sonar
• apple pro tips from eps to pdf
• inkscape
  
  

Labels: computer software, lexicon, software, software tutorial