# convert IP addresses to unsigned long integers
my $addr="192.168.10.2";
my @addrb=split("[.]",$addr);
my ( $addrval ) = unpack( "N", pack( "C4",@addrb ) );

my $mask="255.255.254.0";
my @maskb=split("[.]",$mask);
my ( $maskval ) = unpack( "N", pack( "C4",@maskb ) );

# calculate network address
my $netwval = ( $addrval & $maskval );

# convert network address to IP address
my @netwb=unpack( "C4", pack( "N",$netwval ) );
my $netw=join(".",@netwb);

# print
print( $netw );