incrediBILL - 12:00 am on Jan 29, 2013 (gmt 0)
53 is DNS, I think you meant to say 43 where you said 53.
Geez, I said 43 all over except in one line, typo. I know which port is which ;)
Anyway, I know about telnet, that worked, so did "curl whois.arin.net:43" and the main whois command so it's not a firewall thing.
However, the code like you have posted above flat doesn't work on that server in PHP. If you change the port to 80 it works, but 43 doesn't. It just times out with an error of 0.
Same code works just fine on my other servers and I'm not alone in this specific problem based on other posts I found in several other forums with no resolution.
One of the more baffling things I've run across and the only thing I can think of is maybe arin.net is blocking it when it doesn't have the correct header.