Only if you use a noncompliant DNS server.  Only letters and digits are permitted to start a hostname.<p><a href="http://www.apps.ietf.org/rfc/rfc1123.html#sec-2.1" rel="nofollow">http://www.apps.ietf.org/rfc/rfc1123.html#sec-2.1</a>
<a href="http://www.apps.ietf.org/rfc/rfc952.html" rel="nofollow">http://www.apps.ietf.org/rfc/rfc952.html</a>
<a href="http://www.apps.ietf.org/rfc/rfc921.html" rel="nofollow">http://www.apps.ietf.org/rfc/rfc921.html</a>