Hello sir,
We are a group of administrators trying to set up Auto Proxy using DHCP concept.
We are having a DHCP server with 20 clients .We have also setup a Proxy server (which is a separate machine & is part of DHCP network).
Now the clients in the DHCP network are getting the IP addresses from DHCP server.
If we want to access the internet using Proxy server from any of the clients we had to mention the proxy address in the browser setting of respective client.
But Is there any way that without mentioning the Proxy server address in the client browser setting,the client should be able to access internet.
I mean to say Is there any thing we can mention in the /etc/dhcpd.conf so that if any client opens internet browser he should automatically find the proxy address in the network( i.e. without mentioning the details of proxy in the browser)

If the dhcp server is also your gateway then you can also use transparent proxy.

If all the clients are windows you can use wpad, I'm not sure if any linux distributions support wpad yet.

thanks for response sir
We had already defined the gateway of all the clients including proxy as DHCP IP address.
But in /etc/dhcpd.conf file Can we mention somewhere to automatically search the proxy if any client try to browse the internet.

Is the proxy server and gateway the same machine?

if so you can use transparenty proxy, add a like like...
/sbin/iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8080

but your proxy server has to support it and be setup for it, you didn't say which proxy softwares you're using?

I will try to explain our problem properly---------------------

We are having a WINNT proxy server which is serving around 20 clients. At present the clients are accessing the internet by defining the Proxy address in their browser settings manually.The defaulet gateway of all the clients is IP address of proxy server.

Now our requirement is if we setup Separately a Linux DHCP server and in /etc/dhcpd.conf we define the gateway of all the machines as IP address of Proxy server. Please note that our Proxy itself is also getting IP address from DHCP server.
Now our requirement is we want that all the clients in the DHCP network should be able to detect the Proxy automatically (i.e. without mentioning the IP address of Proxy in client 's browser). And client should get connected to internet automatically through Proxy.
Is there any thing we can do in Linux /etc/dhcpd.conf that our perpose is solved.OR
any other solution-------------------


thanks for the patience------------------------------------------

I don't know how or if winnt can do a transparent proxy the other option is wpad(this is that tick button in it that says automatically detect proxy settings in IE).

To use wpad you'll need a wpad.dat file which looks like...

where proxy.xxxx.com is your proxy server.


To setup wpad, add a host in your domain called "wpad.xxxx.com"
where xxxx.com is your domain.

You'll need to setup a web server with a virtual host with the wpad.xxxx.com name and put the wpad.dat file there.
So the file is accessable via http://wpad.xxxx.com/wpad.dat
IE will try to load this file when it starts up.



another way is to add this to your dhcpd.conf (but I haven't tried it)

option wpad-url code 252 = text;
option wpad-url "!http://wpad.xxxx.com/wpad.dat";