Regexp for validating .au domain names

Question

Hi,

I need a quick regexp for validating that a string is a valid .au domain name. For example:

xxx.com.au
xxx.net.au
xxx.org.au
xxx.biz.au
xxx.--.au

all of these should be considered valid.

This should be pretty simple for someone not as hopeless with regexps as I am. Any ideas?

Answer 1

^[\w\d-\.]+\.au$

That should work fine. You can't really do much else since what comes before the .au might add other second level domains on top of the ones that already exist.

Answer 2

If you want to only allow certain secondary TLDs in the .au space:

/^[a-zA-Z0-9-]+\.(?:com|net|org|biz)\.au$/

Modify the list of secondaries separated by |'s as you desire.

If you don't mind about strictly validating the secondary TLD:

^[a-zA-Z0-9-]+\.\a+\.au$

And if you want to allow more subdomains (i.e. xxxx.yyyy.com.au):

^(?:[a-zA-Z0-9-]+\.)*[a-zA-Z0-9-]+\.\a+\.au$

You may need to use a-zA-Z instead of \a if the particular regex engine you're using doesn't support the latter.

Answer 3

(.*)\.([com|net|org|biz])\.au

Answer 4

/^(?:[a-z0-9\-]+\.){2,}au$/i

For use with preg_match() or other PCRE functions:

if(preg_match('/^(?:[a-z0-9\-]+\.){2,}au$/i', $domain))
    echo "'$domain' is a valid domain\n";
else
    echo "'$domain' is invalid\n";