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KR edition 187 - 188

KR-187* (internic-I)

Some info this edition on the INTERNET (for those curious to know how to get details on domain names on the net)...

  • Did you know that the website: http://www.internic.com/whois.html contains useful info regarding websites (like when they were created; who hosts them, who registered the website etc.)?

  • InterNIC is the website used for ICANN (Internet corp. for Assigned names and addresses).

  • ICANN is the one which manages all domain names (i.e. all the .com, .org etc. addresses).

When one wants to establish a website a few things needed are:

1.) Harddrive space to host the contents of the site.

2.) A server on the host machine (connected to the net) to serve the webpages when they are requested for.

Both of these can be done on our own home PCs which are connected to the net via broadband or dialup even.

  • But for some outsider to reach our webpage they would need to know our IP address (imagine remembering numbers like 124.213.175.131 for each website). If our IP address is fixed this may be feasible but each time we connect to the net our IP address varies; so an outsider wouldn't know our IP address always and wouldn't be able to access our PC.

  • So we need someone on the net to have a fixed IP number that won't change.

  • It would also be better if instead of the IP address we had a name. So we need someone to say that THIS IP ADDRESS can be called using THIS WEBSITE ADDRESS (ex: yahoo.com or google.com).

  • So to map numbers to names we need someone to manage the directory - some sort of universal registry where one can find out that 'this IP number' = 'this website address'.

KR 188* (internic - II)

Hi everyone,

After a little vacation KRs are back...we'll finish off what we started in the last edition before continuing on to other topics...we were discussing about INTERNIC...

  • Instead of IP addresses we use names (called Domain Names) to access websites on the Internet.

  • We have a central registry where details regarding the IP address and domain name are listed (registered). To register a domain name we have to go through a registrar - they'll ensure that our entry is recorded in the registry.

  • When someone types in a domain name, the registry will be accessed to retrieve the corresponding IP address (which is required for all forms of network communication).

  • Every machine on the net has to have a unique IP address to identify it.

  • When we say www.yahoo.com, someone has to look up into the central registry database and find out what the IP address for www.yahoo.com is. This work is done by DOMAIN NAME SERVERS.

  • In Windows the command: ipconfig /all
    will give us the name of the DNS server our PC contacts to resolve domain names.

  • You might have come across scenarios in IE wherein the domain name doesn't work but the IP address works (we would say www.xyz.com and IE will say "page not found" or se- this is generally the case when the domain name server cannot be accessed (or the name server isn't able to resolve the address - i.e. it isn't able to find the ip address for the given domain name).

  • By giving the IP address ourselves the system needn't attempt to access the domain name server and if there is a PC with that IP address then it can be accessed. The domain name server will usually access other servers to resolve the IP address.
    That's all for this edition...Suggestions and KR's welcome;

Ever wondered what MOVE CORRSEPONDING in COBOL means? More on that in the next edition...

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