How to vary a config by host-header

I need multiple sites to all point to a common application, varying by host-header.

While the code / content for each each site is identicial each site does need a unique config, for things like connection strings.

What would be the best approach to set this up?

(The site is actually a S开发者_StackOverflow中文版ilverlight / WCF application, although I don't think that should matter.)

Either use msi installation package and allow set up all these values in installation wizard or use new web.config transformation syntax introduced in .NET 4.0 (you will have separate config and build target for each host header).

Edit - I didn't understand your question first:

You will have to install the application multiple times. You can't have single site with multiple different configs. But you don't have to copy libraries multiple times - you can use links (mklink.exe). It means you will have one central directory holding your shared content like bin directory and you will have separate directory for each site. Each of sites' directories will contain its own web.config and some content placed to root of your site + links to central directory. You will create create separate application for each site in IIS and map single host header to each application.

Other possiblity is handling this in your code and having everything in single web.config but IMO it is pretty bad and dangerous solution.