From: Joel VanderWerf <vjoel@...>
Date: 2008-01-04T03:20:23+09:00
Subject: Re: [OT] Help Request: Dialup, CardBus Cell Phone, etc. Modem IP Loopback Test

Bill Kelly wrote:
> Rubyists,
> 
> If any of you having a "not-always-on" internet connection would
> be willing to try my test program on your systems, I'd be most
> grateful:
> 
> http://tastyspleen.net/~billk/ruby/loopback-test/
> 
> Years ago, some colleagues and I learned that some operating
> systems can attempt to dial out to establish an internet connection,
> even when a program is only trying to do inter-process communication
> using the IP stack over loopback (localhost).  I am hoping that this
> has changed in the intervening years.

Did you rule out DNS lookups? Try setting Socket.do_not_reverse_lookup=true.

Pickaxe II on Socket#addr:

Returns the domain, port, name, and IP address of sock as a four-element 
array. The name will be returned as an address if the 
do_not_reverse_lookup flag is true.

u = UDPSocket.new
u.bind('localhost', 8765)
u.addr   ? ["AF_INET", 8765, "localhost", "127.0.0.1"]
BasicSocket.do_not_reverse_lookup = true
u.addr   ? ["AF_INET", 8765, "127.0.0.1", "127.0.0.1"]

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407