#----------------------------------------------------------
#  Validate against XML schema.
#----------------------------------------------------------
my $xml_schema =
  XML::LibXML::Schema->new(
    location => '/Users/dattanik/Programs/XML/admin_server.xsd' );
eval { $xml_schema->validate($dom); };

if ($@) {
    print "Looks like schema validation has failed. \n";
    print "$@", "\n";
}
else {
    print "XML Schema validation succeeded.\n";
}

##</code><code>##

<xs:element name="application_host_ip">
                <xs:annotation>
                    <xs:documentation>The IP address of the host on which the application is executing.</xs:documentation>
                </xs:annotation>
                <xs:simpleType>
                    <xs:restriction base="xs:string">
                        <xs:pattern value="(\d{1,3}\.){3}\d{1,3}">
                            <xs:annotation>
                                <xs:documentation>This regular expression does a rudimentary check on the IP address.</xs:documentation>
                            </xs:annotation>
                        </xs:pattern>
                        <xs:maxLength value="15"/>
                        <xs:minLength value="7"/>
                        <xs:whiteSpace value="collapse"/>
                    </xs:restriction>
                </xs:simpleType>
            </xs:element>

##</code><code>##

Looks like schema validation has failed 
Element 'application_host_ip' [ST local, facet 'pattern']: The value '123.123.24.56' is not accepted by the pattern '(\d{1,3}\.){3}\d{1,3}'.
Element 'application_host_ip' [ST local, facet 'pattern']: The value '123.123.24.56' is not accepted by the pattern '(\d{1,3}\.){3}\d{1,3}'.