i'm creating a domain forwarding program

[Anon]

i'm trying to create a domain forwarding program using mysql and php

first of all apache is set to by default send all requests to a certain php file.
let's say redirect.php

also DNS settings, nameservers are setup properly for alot of domains.

then i input domains and where the domains should be redirected into mysql db.

ok here is my question~
to figure out what domain the user typed into his/her browser, i'm thinking of using the variables $SERVER_NAME or $HTTP_HOST.

first of all... which should i use
and second of all... does anyone know how reliable this method would be? i.e compatibility with nonstandard browsers, etc...

thanks alot!

[Anon]

you could use anyname you want. but wouldnt this be an easy way to spam you and make mysql unstable?