Next to the fine comments already given, I suggest using a stream (as already suggested) instead of reading the whole data into a list and add a parsing filter (RFC7111 defines CSV fragments).

Assuming you only require fields 7 and 31 and the rest is not interesting:

#!/usr/bin/perl

use 5.18.3;
use warnings;

use Data::Peek;
use Text::CSV_XS qw( csv );

my %ipURL;
csv (
    in       => *DATA,
    out      => undef,
    fragment => "col=7;31",
    on_in    => sub { push @{$ipURL{$_[1][0]}} => $_[1][1]; },
    );

DDumper \%ipURL;
__END__
1,2,3,4,5,6,192.168.102.120,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22
+,23,24,25,26,27,28,29,30,"autodiscover-s.outlook.com/",32
1,2,3,4,5,6,192.168.102.120,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22
+,23,24,25,26,27,28,29,30,"outlook.office365.com/",32
1,2,3,4,5,6,192.168.101.208,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22
+,23,24,25,26,27,28,29,30,"logmeinrescue.com/",32
1,2,3,4,5,6,192.168.101.208,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22
+,23,24,25,26,27,28,29,30,"logmeinrescue.com/",32
[download]

--->

{   '192.168.101.208' => [
        'logmeinrescue.com/',
        'logmeinrescue.com/'
        ],
    '192.168.102.120' => [
        'autodiscover-s.outlook.com/',
        'outlook.office365.com/'
        ]
    }
[download]

As a side note: if a hostname appears more than once for the same IP, using a hash instead of a list might be more memory-friendly and easier to consume:

my %ipURL;
csv (
    in       => *DATA,
    out      => undef,
    fragment => "col=7;31",
    on_in    => sub { $ipURL{$_[1][0]}{$_[1][1]}++ },
    );

DDumper \%ipURL;
[download]

-->

{   '192.168.101.208' => {
        'logmeinrescue.com/' => 2
        },
    '192.168.102.120' => {
        'autodiscover-s.outlook.com/' => 1,
        'outlook.office365.com/' => 1
        }
    }
[download]

---

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