my %USERS;
my @all_strips = ();       ## <-- new
foreach my $file (<passwds.*>) {
   open(PASSWD,$file)
       or warn "Could not open $file:$!\n", next;
   my $strip=$file;
   #strips passwd. from passwd.server
   $strip =~ s/passwds\.//;
   push(@all_strips, $strip);   ## <-- new
   while(<PASSWD>) {
       my($login,$gcos) = (split(':',$_))[0,4];

       $USERS{$login}{$strip} = 1;  ## This way you keep track of
                                    ## which login/strip combinations
                                    ## have been seen
   }
   close(PASSWD);
}
open(NEWFILE,">file3") or die "Can't open file3: $!\n";
foreach my $login (sort keys %USERS) {
    print NEWFILE "$login:",
        # Substitute X in where no strip was found
        join(':', map { $USERS{$login}{$_} ? $_ : 'X' }
                      @all_strips),
        "\n";
}
close NEWFILE;
print "the Active Servers listing is done\n";