[thelist] PHP: getting domain names from a url - being foiled by .co.uk addresses

Dunstan Orchard dunstan at 1976design.com
Sun Dec 7 18:10:16 CST 2003

Hey everyone,

Sorry I didn't reply last night, I fell asleep at my desk and only woke 
up when I fell off the yoga ball I use as a chair. It gave me a bit of a 
shock I can tell you :o)

Anyway, where have I reached with this problem - well:

[1] Manuel suggested exploding the url at the dots.
[2] Kelly suggested doing the same and then using a lookup table to 
determine if multiple dots represented subdomains, or a url with a 
.co.uk address or similar.
[3] Tony and Ken suggested looking up the IP address and then using that 
to look up the domain name.

I like the last suggestion the best (seemes like much less work) but of 
the first three examples I tried, I found two problems:

ip =
hostname = asda.co.uk

news.yahoo.com (or indeed just 'yahoo.com')
ip =
hostname = story1.news.vip.dcn.yahoo.com

dev.[secret url].org
ip = xxx.xxx.xxx.xxx
hostname = xxx-xx-xx-xx.[secret].net

So, although it works on most straight forward urls, 2 of the first 3 I 
tried brought back some horrible results - though they're obviously correct.

Does anyone know of a way to return the public-facing urls?

Thanks again,

- Dunstan

Dorset, England
Work: http://www.1976design.com/
Play: http://www.1976design.com/blog/
Learn: http://webstandards.org/

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