Upon asking HostGator about a null route, they gave example of it:
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Due to a Denial of Service Attack to the
server, we have been forced to null route
the server's primary IP address and
assign a new address for its hostname
and primary DNS server. This may cause
issues with DNS propagation and
accessibility for a few hours while we
make these configuration changes. Some
accounts may have been moved to
another IP address. If you are unable to
access your site on this server, please
contact support. Denial of Service attacks
are attacks in which a resource is tied up
with garbage information sent by
attacking servers, keeping legitimate
attempts to access a resource from
getting through. This form of attack does
not involve any type of security
compromise, it only makes the server
difficult to reach, and it is temporary. We
apologize for any inconvenience that this
may cause and thank you for your
continued patience.
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Basically, Liberty Reserve IP has been null routed due to Denial of Service Attack on their servers. Let's just hope for the best !