Can a machine with a single DNS name have multiple IP addresses If so give a possible example If not then explain why not?

Answer 1

Yes one DNS name can resolve to multiple IP addresses. This practice is called load balancing

http://en.wikipedia.org/wiki/Load_balancing_(computing)

and as an example a dig lookup on www.Google.com shows that www.google.com at this particular moment can be resolved to the following three IPs:

209.85.229.104

209.85.229.147

209.85.229.99

There might be even more servers associated with this domain and these might have been cached by a DNS server somewhere ( these cached addresses are meant to last for about 5 mins ( dig output :) )). For a detailed explanation use wikipedia and look up the dig utility for Linux. The dig tutorial helps in understanding how DNS works in the background. (The dig output is pasted at the end)

The only way you can have more than one ip address on a computer is if you have more than one internet service. Even if you had 3 computers connected through a router wich your modem was hooked up to all 3 would have the same ip address unless you where to use a proxy on your computer to trick people into thinking you where somewhere else but most of these that you find that are simpilar are very easy to crack so if you're planning on trying to use them to hack/break the law then don't bother because you will get caught and you will get to sent to jail for several years if you are over the age of 16. Even if you are under 16 you're still most likely getting sent to jail they just might be a little more leniant (I bet I spelled that wrong.)

OR

IP has nothing to do with netbios. In fact, netbios is a layer 5 protocol and IP exists on layer 3 of the OSI model.

Also, networks are hierarchical. This means that no two interfaces can have the same address if they are on the same network.

DNS is there to translate your typed URL into a 32 digit binary number that the computer recognizes.

For example: www.mywebsite.com is translated into 110000000010101000010001010001110. This is what the computer reads as the IP address.

To understand the long IP address, use dotted octets. This is divided into four "octets" - 4 sets of 8-bit numbers. 11000000.10101000.01000101.00001110.

This is translated into: 11000000 = 192 10101000 = 168 01000101 = 69 00001110 - 14

So, the IP address of www.mywebsite.com is 192.168.69.14

dig www.google.com

; <<>> DiG 9.7.1-P2 <<>> www.google.com

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52869

;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:

;www.google.com. IN A

;; ANSWER SECTION:

www.google.com. 134900 IN CNAME www.l.google.com.

www.l.google.com. 298 IN A 209.85.229.104

www.l.google.com. 298 IN A 209.85.229.147

www.l.google.com. 298 IN A 209.85.229.99

;; Query time: 19 msec

;; SERVER: 192.168.1.254#53(192.168.1.254)

;; WHEN: Thu Apr 21 21:45:07 2011

;; MSG SIZE rcvd: 100