How are you using firefox? Are you using it only with IP addresses, no host names?

Thanks for reply.
No I use host names only in firefox (also lynx). This is what I feel strange how firefox is able to resolve those host names??? How can I do the same.

Thanks for reply.
Both ping and given nslookup failed.
Output:
and with that url address I landed on google home page.

I also now believe port 53 might be closed. Its tough to ask the admins as they generally don't reveal all these things to students.
Are there any http equivalents of these commands. How does my browser resolve hosts then(firefox and lynx).

There is only one way, how you can resolve IP is set up your own DNS - BIND. You can download database of domain names and IP. But, if you start to use internet, your admins easily can close the rest of it.

Also you can read about socks proxy - they also can resolve IP on server side. But not many browsers can use them.

You can also make a tunnel to someone with unlimited internet, and use its internet.

But easiest way is ti type on browser address bar:
And resolve domain there.


The problem is when admins have hidden DNS server, they knew what they are doing, idea was to prevent people to use internet.

Thanks for reply.
Yes, I also now believe only way possible is to use some web dns query service.
Any how thanks to all great guys here for their kind replies. Only one questions remains:

Kindly do close this thread after answering this question. I don't want to trouble you people any more. You have been very kind to a newbie like me.
Thanks again.

There's an option in firefox network configuration that, when selected, tells firefox to use the proxy server for all protocols. In principle, firefox can also try to get proper configuration from a proxy server automatically. Who configured firefox?

Thanks for reply!!
I myself configured firefox:
Preferences->Advanced->Network->Settings
I entered the proxy address given by college in the proxy field and selected "Use this for all protocols." So how does firefox use my proxy to resolve host. Can I mimic it with some code.
Latest Update:
Yesterday night tried nc -v google.com 80
It also was not working even with IP address of google and other many sites. However was working on LAN computers.
OUTPUT:
Google(both host address and ip address):
However on LAN computers it worked(only some and strange still they appears to be some cisco machines!!!):
Does netcat also suffers from the same problem. But with ip-address give(as in case of google.com) why it fails as it need not do any host lookup??

Well if the machines on the LAN to which you referred have some way of using the proxy, you might want to find out if there's something they have, that you should have.

Also, now that we know you're not using IP addresses in firefox, there may be some other possibilities as well.

I don't know that I've ever had to worry about it myself. so I never used them. But I have some vague recollection about various things for working with a proxy. There was something with some name like proxy client that I believe was a substitute for some standard libraries that ultimately would make system calls. The substitute libraries instead made calls to some facility that was installed to handle various things through the proxy. There was also something with a name like proxy chains that I believe ran other commands within it's environment, in which it talked through the proxy. I almost thought I had heard of something designed for use with squid. You can check at source forge and places of that type for "projects" that might do what you want. I believe some of these things were years ago, don't know if they work on newer versions of Linux, specifically RHEL, or if they are still being maintained, if there's anything newer, etc. But it's probably worth a look...

Thanks for reply!
I am checking for such libraries. One alternative I found was that of Curl library. Another one in python(although not much clear about it) provide library functions for dns queries and also take care of proxy. So it seems i will have to write my own host command :-0 well hope it will be a exciting adventure.
Thanks to all the kind people for their sincere reply. If i find any breakthrough I shall share here.

From what I can understand from the various bits of information on the network being discussed here, the intention of the network administrators there was to prevent direct internet access via anything short of the proxy server. If you can't send DNS requests out whatever gateway being utilized there, you're probably not going to have direct access to anything else, either. There's a good chance that whatever gateway you have assigned via your DHCP lease isn't the gateway being used by the proxy server you use for internet access as well.

After going through the process of setting up something to resolve DNS requests via the proxy server there, you're still more than likely not going to be able to send whatever traffic you generate due to the fact that it appears the security devices in place don't allow the traffic and/or you don't know what the actual internet access device is.

Let us know when the network admins there disable your network access. That's what I've done in the past with those that do things on the network they shouldn't be doing. That forces the offending party to inquire about their network access being broken.

Hi dheerajsuthar2008,

devwatchdog has expressed a valid principle. I too have had to shut people down on a network when they were doing something that I felt they shouldn't be doing.

I don't know what your overall goal is. I've been functioning on the basis that if the proxy allowed you to resolve DNS via firefox, for general Internet sites, that you were allowed to use the internet on an *outgoing* basis. That perhaps the admins just wanted to prevent people from running servers which could accept *incoming* connections, and result in a lot of extra traffic over their internal network. If the admins just didn't want you to set up servers, or some such, and you just wanted to learn by figuring out how firefox does DNS via the proxy, to me it seemed like no big deal. I also wondered if perhaps there was some instructions for setting things up, that you just hadn't followed. Maybe you just took a guess at how do set things up yourself. :-)

If instead the situation is that you are only able to get to web sites within a college campus, and not outside on the Internet in general, or if your goal is to do a great deal more than just poke around with DNS, if instead you are trying to do all sorts of things the admins probably don't want you to do, you might want to consider stopping.

My sincere thanks to all those kind repliers!
Although problem still persists and appears to be insolvable due to great restrictions of my net admin, I learnt a great deal from your replies. My sincere thanks to all of you once again. Moderators can kindly close this thread.