My network range

netrange.pl <network base/CIDR notation> (e.g. 192.168.1.0/25 is half of a private class C). Returns the number of hosts, netmask and broadcast address.

#!/usr/bin/perl
@VALUE = split (/\//, $ARGV[0]);
@OCTETS = split (/\./, $VALUE[0]);
$calculated = 2**(32 - $VALUE[1]);
$OCTETS[3]--; # (base counts as one...)
$OCTETS[3] += $calculated;
$broadcast = join (".", @OCTETS);

print qq~
$calculated hosts
Base is $VALUE[0]
Broadcast is $broadcast~;
[download]

Comment on My network range Download Code

Replies are listed 'Best First'.
Re: My network range by atcroft (Abbot) on Dec 08, 2001 at 11:57 UTC
Where you have `$calculated = 2**(32 - $VALUE[1]);` [download] you might try this instead (especially if this code gets performed over and over and ove...) : `$calculated = 1 << (32 - $VALUE[1]);` [download] A bit-wise shift, especially in the case where you're dealing with powers of two, would likely be much less computationally expensive that exponentiation via multiplication. (That's my guess-can someone verify this?)	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re: My network range
by atcroft (Abbot) on Dec 08, 2001 at 11:57 UTC

Where you have

$calculated = 2**(32 - $VALUE[1]);
[download]

$calculated = 1 << (32 - $VALUE[1]);
[download]

A bit-wise shift, especially in the case where you're dealing with powers of two, would likely be much less computationally expensive that exponentiation via multiplication. (That's my guess-can someone verify this?)

[reply]
[d/l]
[select]