Teach dak IP resolution

[Dak]

OK, iv googled and read, but im a tad confused about a few parts of how urls are resolved into IPs -- mainly the diference between a host and a domain.

 

Could we ignore all the complications involving the host file/domain name cache/ISP-DNS/root-DNS etc; im not too fused with where the ip is resolved from, more how it is resolved.

 

So, take this site:

 

38.118.74.97

 

thats SFN. the url for the main page is:

 

http://www.scienceforums.net:80/index.php?'>http://www.scienceforums.net:80/index.php?

|__|...|___________________||.|_______|

..|....................|...............port......|

protocol.........middle bit..............end bit

 

The protocol tells your computer how to talk to the site which it is looking for -- in this case, http (hyper-text transfer protocol). its a protocol which allows easy transfer of html, gif, flash files etc. ftp is a good protocol to transfer files etc. its basically the language that its using whilst transfering data

 

the port tells your computer which TCP port to connect to on the computer which it is looking for. 80 is default.

 

the end bit refers to a path on the computer: in this case index.php?. works identicle to normal path names, ie the file is called index with an extention of php (dunno what the ? means). sometimes it can have #x, which points the browser at the anchor 'x' on the page.

 

(is that right so far?)

 

middle bit: this is where i get confused.

 

http://www.scienceforums.net

|___||__________||__|

...|............|...........|_________top-level domain

..host.....domain

 

righty dokums... top-level domain. that, i understand. it basically allows more than one site to have the same name. so, there is a http://www.scienceforums.net, and a http://www.scienceforums.com. as well as allowing duplication of names, it gives a bit of info about the site (gov is a govournmental site, com is a commercial one etc).

 

its the host and domain that i dont understand... can someone explain?

 

id guess that its the domain+top-level domain whos IP gets looked up (eg, 38.118.74.97 = scienceforums.net

 

but what does the host do?

 

If you take of the host of the address above (the 'www' bit in this case), then it goes to the home page, but without you being logged in...

 

http://www.scienceforums.net/index.php

 

http://scienceforums.net/index.php

 

so, whats the deal with host-names? what do they do?

[Newtonian]

its all to do with servers...and how they interact between your computer and the server...for instance http//www is hyper thread on the world wide web....(which means to search for a page or site using standard www browser,and viewing it).....absolutely no good if your wanting to actually set up an FTP connection.Try to connect FTP with the http://www.browser and you are directed to a page cannot be displayed.Now use your FTP written software and put in eftp//www and bingo your connected to the actual server direct to DL and UL.

Basically if i can put it correctly the www tells the net your wanting to access the site or page using the standard www browser so your wanting it to be displayed.Simply allowing the GET and POST command using standard browser(this enables the bridging of differing software..you know macs n windows etc....if your all using a standard it makes it easy to get along)

I fix and crack not hack so really not into all the protocols as such but hope it helps !!!

[Dave]

There's not a lot to actually get about it tbh. Each TLD has rather a lot of names registered under it (i.e. scienceforums.net, abc.net, othername.net etc). It keeps a record of which machines are supposed to be resolving the domain names.

 

So, when you look up the address for http://www.scienceforums.net, your IP resolver will go along to the root nameservers at .net, and say "hey, who's hosting scienceforums.net?" You then get pointed to the nameservers hosting the domain, and then you say to them "do you have a subdomain called www?" It goes "yeah, the IP address is 38.118.74.97".

 

The point of it all is to enable you to point to a lot of IP addresses. Say that we had 20 different machines each hosting a webserver. It would be a pain if we could only resolve scienceforums.net; it'd be useful to have some kind of name for each machine (i.e. www1.scienceforums.net, www2, ..., www20). Also, say you have an FTP service running on a different machine or attached to a different interface. Then it would be prudent to have ftp.scienceforums.net pointing to that IP instead. Similarly for things like mailservers, etc. Whilst it's not very useful for people running things off of 1 connection, for large corporations it's extremely useful.

[Dak]

i assume nameserver = dns?

 

so you could essentially have different ip adresses registered to the same name, and encorporated into one 'website'?

 

ie, http://www.scienceforums.net and www2.scienceforums.net would both contain the name scienceforums.net (easyer for the human) but would both resolve into different ip addresses, pointing them to the different machines but retaining the 'scienceforums.net' part, to unify the different websites under the same domain name?

 

and i assume that, once youv registered a domain, no-one can register a different host under that domain (so noone could spoof us by registering home.scienceforums.net)?

 

if that be the case, may i ask, for an example, what subdomains/hosts scienceforums.net has registered?

[Newtonian]

and i assume that' date=' once youv registered a domain, no-one can register a different host under that domain (so noone could spoof us by registering home.scienceforums.net)?

[/quote']

Oh its very simple to create our login page to steal peoples ID's.....the point is why would someone want to? theres no profit for the culprit.

Its pretty pointless to steal Sayo's Id and go online to call everyone ....who would believe it wasn't him anyway llllooollll:-)

[Dak]

for another site though, (eg one involving money) there would be more profit in spoofing them.

 

are you telling me that i could register the url home.scienceforums.net ???

[Dave]

are you telling me that i could register the url home.scienceforums.net ???

 

No, you can't do that. Once you've registered a domain, you're given complete control over it, including all sub-domains, nameservers, MX records, etc.

[Dak]

righty dokums.

 

so, everything between the http:// and the colon of the place where the port number would go if we had to put it in has a different IP number...

 

howcome scienceforums.net is the same ip as http://www.scienceforums.net? is www the only host?

 

and how come my logon details arent remembered for scienceforums.net (is it to do with the fact that my cookie, with my logon details, is named "www.scienceforums.net"?