diff --git a/LANforge/Utils.pm b/LANforge/Utils.pm
index c0d56c51..e65ec0ec 100644
--- a/LANforge/Utils.pm
+++ b/LANforge/Utils.pm
@@ -3,7 +3,8 @@ use strict;
 use warnings;
 use Carp;
 use Net::Telnet;
-use bigint;
+#use bigint;
+use Math::BigInt;
 $| = 1;
 #$SIG{ __DIE__ } = sub { Carp::confess( @_ ) };
 #$SIG{ __WARN__ } = sub { Carp::confess( @_ ) };
@@ -1160,18 +1161,23 @@ sub expand_unit_str {
 }
 
 sub mac_add {
-   my ($first_mac, $second_dec) = @_;
+   my ($self, $first_mac, $second_dec) = @_;
    $first_mac =~ s/[:]//g if ($first_mac =~ /[:]/);
-   
    $first_mac = "0x".$first_mac if ($first_mac !~ /^0x/);
-   
-   my $newdec = (0+$second_dec) + hex($first_mac);
-   my $newhex = sprintf("%x", $newdec);
+   my $newdec = Math::BigInt->new($first_mac);
+   $newdec->badd(0+$second_dec);
+   my $pad = Math::BigInt->new('0x1000000000000');
+   $newdec->badd($pad);
+   my $newhex = "".$newdec->as_hex();
    my $rv = "";
+   $newhex = substr($newhex, -12); # we begin 0x100...much bigger than we need
    for (my $i = length($newhex); $i > 0; $i-=2) {
       $rv = substr($newhex, $i-2, 2).":$rv";
    }
-   return substr($newhex, 0, -1);
+   $rv =substr($rv, 0, -1);
+   undef($newdec);
+   undef($pad);
+   return $rv;
 }