A Waage Blog » getaddrinfo http://qugstart.com/blog Ruby, Rails, Life Thu, 10 Nov 2011 00:35:02 +0000 http://wordpress.org/?v=2.8.4 en hourly 1 Resolve a hostname from an IP address in Ruby (Reverse-DNS) http://qugstart.com/blog/ruby-and-rails/resolve-a-hostname-from-an-ip-address-in-ruby-reverse-dns/ http://qugstart.com/blog/ruby-and-rails/resolve-a-hostname-from-an-ip-address-in-ruby-reverse-dns/#comments Fri, 09 Oct 2009 21:47:43 +0000 Andrew Waage http://qugstart.com/blog/?p=10 It sounds easy, but I tried a lot of things before finding the solution I used.

I tried using:

`host 66.249.67.49` or
`nslookup 66.249.67.49`

These were fine, but it seems a bit hacky to use the shell. Also, it would require some sort of parsing to get the hostname that I want.

Browsing the web, I found a couple solutions that almost worked.

s = Socket.getaddrinfo('66.249.67.49',nil)
hostname = s[0][2]

This solution worked in IRB, worked in console, but for some reason would not work when I was running my mongrel server and trying to perform the exact same method call from a web-browser. ( I still don’t know why).

Digging around a bit more, I came up with this simple solution:

host = Resolv.new.getname('66.249.67.49')

Is it really that easy?? Give it a shot and let me know your thoughts !!

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