For business data, if the data is private I would use a secured connection, otherwise a forms authentication is sufficient.
If you do decide to use a secured connection, please note that I do not have experience with securing websites, I am just recanting off what I encountered during my own personal experience. If I am wrong in anyway, please feel free to correct me.
What should I do to prepare my website for https. (Do I need to alter the code / Config)
In order to enable SSL (Secure Sockets Layer) for your website, you would need to set-up a certificate, code or config is not altered.
I have enabled SSL for an internal web-server, by using OpenSSL and ActivePerl from this online tutorial. If this is used for a larger audience (my audience was less than 10 people) and is in the public domain, I suggest seeking professional alternatives.
Is SSL and https one and the same...
Not exactly, but they go hand in hand! SSL ensures that data is encrypted and decrypted back and forth while you are viewing the website, https is the URI that is need to access the secure website. You will notice when you try to access http://secure.mydomain.com it displays an error message.
Do I need to apply with someone to get some license or something.
You would not need to obtain a license, but rather a certificate. You can look into companies that offer professional services with securing websites, such as VeriSign as an example.
Do I need to make all my pages secured or only the login page...
Once your certificate is enabled for mydomain.com every page that falls under *.mydomain.com will be secured.
4.Do I need to make all my pages secured or only the login page...
Just keep the login page under https
this will ensure there is no overhead when browsing other pages. the condition is you need to provide correct authentication settings in the web config. This is to ensure users who are not logged in will not be able to browse pages that would need authentication.
What kind of business data? Trade secrets or just stuff that they don't want people to see but if it got out, it wouldn't be a big deal? If we are talking trade secrets, financial information, customer information and stuff that's generally confidential. Then don't even go down that route.
I'm wondering whether I need to use a
secured connection (https) or just the
forms authentication is enough.
Use a secure connection all the way.
Do I need to alter the code / Config
Yes. Well may be not. You may want to have an expert do this for you.
Is SSL and https one and the same...
Mostly yes. People usually refer to those things as the same thing.
Do I need to apply with someone to get some license or something.
You probably want to have your certificate signed by a certificate authority. It will cost you or your client a bit of money.
Do I need to make all my pages secured or only the login page...
Use https throughout. Performance is usually not an issue if the site is meant for internal users.
I was searching Internet for answer,
but I was not able to get all these
points... Any whitepaper or other
references would also be helpful...
I think you are getting confused with your site Authentication and SSL.
If you need to get your site into SSL, then you would need to install a SSL certificate into your web server. You can buy a certificate for yourself from one of the places like Symantec etc. The certificate would contain your public/private key pair, along with other things.
You wont need to do anything in your source code, and you can still continue to use your Form Authntication (or any other) in your site. Its just that, any data communication that takes place between the web server and the client will encrypted and signed using your certificate. People would use secure-HTTP (https://) to access your site.
Do I need to apply with someone to get
some license or something.
You can buy an SSL certificate from a certificate authority or use a self-signed certificate. The ones you can purchase vary wildly in price - from $10 to hundreds of dollars a year. You would need one of those if you set up an online shop, for example. Self-signed certificates are a viable option for an internal application. You can also use one of those for development. Here's a good tutorial on how to set up a self-signed certificate for IIS: Enabling SSL on IIS 7.0 Using Self-Signed Certificates
Do I need to make all my pages secured
or only the login page..
Use HTTPS for everything, not just the initial user login. It's not going to be too much of an overhead and it will mean the data that the users send/receive from your remotely hosted application cannot be read by outside parties if it is intercepted. Even Gmail now turns on HTTPS by default.
@balalakshmi mentioned about the correct authentication settings. Authentication is only half of the problem, the other half is authorization.
If you're using Forms Authentication and standard controls like <asp:Login> there are a couple of things you'll need to do to ensure that only your authenticated users can access secured pages.
In web.config, under the <system.web> section you'll need to disable anonymous access by default:
Any pages that will be accessed anonymously (such as the Login.aspx page itself) will need to have an override that re-allows anonymous access. This requires a <location> element and must be located at the <configuration> level (outside the <system.web> section), like this:
Be aware that the location's path attribute is relative to the web.config folder and cannot have a ~/ prefix, unlike most other path-type configuration attributes.