in reply to newb regular expression question

What do need exactly? The block or a specific line? How about 
use strict;
use Data::Dumper:

my($lease, %info);
while(<DATA>) {
  next
    unless (($lease) = /^lease \s+ ((?:\d+.?)+) \s+ \{$/x) .. /^\}$/;
  push @{ $info{$lease} } => { $1 => [split ' ', $2] }
    if /^\s+ (\S+) \s+ (.*);/x;
}


print Dumper(\%info);

__DATA__

lease 10.2.56.40 {
        starts 3 2003/08/20 10:37:28;
        ends 3 2003/08/20 22:37:28;
        hardware ethernet 00:20:af:52:12:0f;
        uid 01:20:af:52:12:0f;
        client-hostname "Telephone";
}
lease 10.2.56.75 {
        starts 3 2003/08/20 09:57:11;
        ends 3 2003/08/20 21:57:11;
        hardware ethernet 00:ef:18:ae:52:83;
        uid 01:00:ef:18:ae:52:83;
        client-hostname "beast";
}
lease 10.2.56.77 {
        starts 2 2003/08/19 21:13:05;
        ends 3 2003/08/20 21:13:05;
        hardware ethernet 00:02:95:9b:78:18;
        uid 01:02:0b:95:9b:78:18;
}

[download]
Which creates a hash of arrays of hashes of arrays and outputs this 

$VAR1 = {
          '10.2.56.75' => [
                            {
                              'starts' => [
                                            '3',
                                            '2003/08/20',
                                            '09:57:11'
                                          ]
                            },
                            {
                              'ends' => [
                                          '3',
                                          '2003/08/20',
                                          '21:57:11'
                                        ]
                            },
                            {
                              'hardware' => [
                                              'ethernet',
                                              '00:ef:18:ae:52:83'
                                            ]
                            },
                            {
                              'uid' => [
                                         '01:00:ef:18:ae:52:83'
                                       ]
                            },
                            {
                              'client-hostname' => [
                                                     '"beast"'
                                                   ]
                            }
                          ],
          '10.2.56.77' => [
                            {
                              'starts' => [
                                            '2',
                                            '2003/08/19',
                                            '21:13:05'
                                          ]
                            },
                            {
                              'ends' => [
                                          '3',
                                          '2003/08/20',
                                          '21:13:05'
                                        ]
                            },
                            {
                              'hardware' => [
                                              'ethernet',
                                              '00:02:95:9b:78:18'
                                            ]
                            },
                            {
                              'uid' => [
                                         '01:02:0b:95:9b:78:18'
                                       ]
                            }
                          ],
          '10.2.56.40' => [
                            {
                              'starts' => [
                                            '3',
                                            '2003/08/20',
                                            '10:37:28'
                                          ]
                            },
                            {
                              'ends' => [
                                          '3',
                                          '2003/08/20',
                                          '22:37:28'
                                        ]
                            },
                            {
                              'hardware' => [
                                              'ethernet',
                                              '00:20:af:52:12:0f'
                                            ]
                            },
                            {
                              'uid' => [
                                         '01:20:af:52:12:0f'
                                       ]
                            },
                            {
                              'client-hostname' => [
                                                     '"Telephone"'
                                                   ]
                            }
                          ]
        };

[download]

See. perlre and the ever helpful YAPE::Regex::Explain for more info on the regexes used above and perlreftut, perldsc and tye's References quick reference for more info on data structures and dereferencing them.
HTH

_________
broquaint

update: modified code to store the per lease values as an array

In Section Seekers of Perl Wisdom