or download this
($Core) = &connect( $Core, $user, $pass );
@Output = $Core->capture( "show ip route $IPNumber" ) or
...
@Subnet = split( /\./, $Subnet );
$RouterIP = join( '.', $Subnet[0], $Subnet[1], $Subnet[2], '1' );
print( " Router: [$Rname]\t Router IP: [$RouterIP]\n" );