iis 6 - Run Custom C# Code In A "Web Site" From An IIS "Application" -

i have tough question here , tap wisdom of masses ensure approaching issue in efficient way possible.

goal: move 78 web applications (all configured iis application under root website) windows server 2003 box 2012 box little coding possible. 2012 box has different subdomain "xxx2.blah.com" , 03 server mapped "xxx.blah.com" server. in short, user bookmarks won't work once migrate want write redirection utility assist getting users new xxx2.blach.com location without them noticing.

current state:it important note each application under root website in iis6 configured run under own, , shared, app pools. of applications have querystring values appended end of .net request want retain because affects ui , other business logic coded.

we thinking of removing files within each application force iis return 404. once 404 occurs, wanting run our custom utility lookup equivalent url is. since 404 "error" intents , purposes, thinking "handle" error (asp.net 2.0 : best practice writing error page)

is possible write code once, add logic global.asax file in root website, , somehow instruct each web application under root site execute code in parent site? know each run under own app pool , may mean cannot pass execution off onto application wrong. in addition, hoping not have copy/paste code 78 times. general "best practices" or advice appreciated. also, adjusting on network not option old xxx.blah.com on different network new xxx2.blah.com network.

@carl

thank much. missed variables available me purpose! final solution me set "redirect to" textbox "http://xxx2.blah.com$v?updatenote=true&$p". enables redirection occur both path , querystring name/value pairs in tact , allowed me append own value application detect , display "this page has moved" message user.

thank carl! da man.