 <p>No, an iPhone application can only change stuff within its own little sandbox. (And even there there are things that you can't change on the fly.)</p> <p>Your best bet is probably to use the servers IP address rather than hostname. Slightly harder, but not <em>that</em> hard if you just need to resolve a single address, would be to put a DNS server on your Mac and configure your iPhone to use that.</p>