s0ttle has the rewrite correct. However, Perl idiom (and tradional coding practice) would dictate declaring a variable in tightest scope possible. Thus, I moved the my to within the while loop.

#!/usr/bin/perl -w
# IP ranger

# If you're on 5.6.0 or higher, add the following two lines
# and remove the -w

#use 5.6.0;
use strict;
#use warnings;

open(IPFILE,"<iplist.txt"); # open readonly
    || die "Could not open iplist.txt:$! \n";

while (<IPFILE>) {    
    chomp; 

    my ($stip,$edip) = split ':', $_, 2; # split(/:/);

    print "$stip\n";
    print "$edip\n";

    my @openip = split '.', $stip; # split(/\./,$stip);
    my $count = @openip;

    print "$count\n"; 

    # you can avoid the creation of the $count
    # variable and use the following statement               
    # print scalar(@openip), "\n";
                

#    for ($i = 0; $i <= 4; $i++) {
#        print "@srtip\n";
#    };
};

close(IPFILE);
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