"...could you try this out?"

Why not, nice invitation:

karls-mac-mini:monks karl$ perl -MData::Dumper -e '$hash{'cl_ip'} = "2
+9988" + 0;print Dumper(\%hash);'$VAR1 = {
          'cl_ip' => 29988
        };
[download]

But: so what ;-)

Update:

D'oh! Mille Regretz!

#!/usr/bin/env perl                                                   
+                                            

use JSON::XS;
use Data::Dumper;

my %hash = ( cl_ip => 209890 );

my $json = encode_json \%hash;

print Dumper( \%hash );

print qq($json\n);

$hash{ cl_ip } += 0;

$json = encode_json \%hash;

print Dumper( \%hash );

print qq($json\n);

__END__

karl-mac-mini:monks karl$ ./json.pl                                   
+                                            
    $VAR1 = {                                                         
+                                            
          'cl_ip' => 209890                                           
+                                            
};                                                                    
+                                            
{"cl_ip":209890}                                                      
+                                            
$VAR1 = {                                                             
+                                            
          'cl_ip' => 209890                                           
+                                            
        };                                                            
+                                            
{"cl_ip":209890}
[download]

Update2:

#!/usr/bin/env perl                                                   
+                                            

use JSON::XS;
use Data::Dumper;

my %hash = ( cl_ip => 209890 );

my $json = encode_json \%hash;

print Dumper( \%hash );

print qq($json\n);

$hash{ cl_ip } += 0;

$json = encode_json \%hash;

print Dumper( \%hash );

print qq($json\n);

$hash{ cl_ip } = "209890";

$json = encode_json \%hash;

print Dumper( \%hash );

print qq($json\n);

__END__
$VAR1 = {
          'cl_ip' => 209890
        };
{"cl_ip":209890}
$VAR1 = {
          'cl_ip' => 209890
        };
{"cl_ip":209890}
$VAR1 = {
          'cl_ip' => '209890'
        };
{"cl_ip":"209890"}
[download]

I'll give it up for tonight before i produce more shit...

Update3:

I'll give it up...

I don't:

#!/usr/bin/env perl

use JSON::XS;
use Data::Dumper;
use strict;
use warnings;

my %hash = ( cl_ip => 209890 );

print Dumper( \%hash );

print qq(\n);

my $json = encode_json \%hash;

print qq($json\n\n);

#------------------------------

$hash{cl_ip} += 0;

print Dumper( \%hash );

print qq(\n);

$json = encode_json \%hash;

print qq($json\n\n);

#------------------------------

$hash{cl_ip} = "209890";

print Dumper( \%hash );

print qq(\n);

$hash{cl_ip} += 0;

print Dumper( \%hash );

print qq(\n);

$json = encode_json \%hash;

print qq($json\n\n);

__END__

karl-mac-mini:monks karl$ ./json.pl 
$VAR1 = {
          'cl_ip' => 209890
};

{"cl_ip":209890}

$VAR1 = {
          'cl_ip' => 209890
};

{"cl_ip":209890}

$VAR1 = {
          'cl_ip' => '209890'
};

$VAR1 = {
          'cl_ip' => 209890
};

{"cl_ip":209890}
[download]

My best regards, Karl