Use an array reference as a switch to point to whichever array is appropriate depending on the section title. Then there is no need to back up a line.

use strict;
use warnings;

use feature qw{ say };

open my $inFH, q{<}, \ <<__EOD__ or die $!;
    Relay access denied (total: 5)
           1   46.183.217.174
           1   46.183.220.137
           1   46.183.220.138
           1   46.183.220.139
           1   46.183.223.239
    Sender address rejected: Access denied (total: 5)
           1   47.183.223.239
           1   219.38.243.204
           1   183.29.8.198
           1   183.29.9.133
           1   183.29.9.135
    Relay access denied (total: 8)
           1   218.38.243.204
           1   185.29.8.198
           1   185.29.9.133
           1   185.29.9.135
           1   46.183.217.162
           1   46.183.217.165
           1   46.183.217.169
           1   91.236.75.169
__EOD__

my @rad;
my @sad;
my $raSwitch;

while ( <$inFH> )
{
    if ( m{\s+\d+\s+(\S+)} )
    {
        push @{ $raSwitch }, $1;
    }
    elsif ( m{Relay access denied} )
    {
        $raSwitch = \ @rad;
    }
    elsif ( m{Sender address rejected} )
    {
        $raSwitch = \ @sad;
    }
    else
    {
        warn qq{Line not recognised: $_};
    }
}

say  q{Relay access denied:};
say qq{     $_} for @rad;

say  q{Sender address rejected:};
say qq{     $_} for @sad;

[download]

The output.

Relay access denied:
     46.183.217.174
     46.183.220.137
     46.183.220.138
     46.183.220.139
     46.183.223.239
     218.38.243.204
     185.29.8.198
     185.29.9.133
     185.29.9.135
     46.183.217.162
     46.183.217.165
     46.183.217.169
     91.236.75.169
Sender address rejected:
     47.183.223.239
     219.38.243.204
     183.29.8.198
     183.29.9.133
     183.29.9.135

[download]

I hope this is helpful.

Cheers,

JohnGG

In reply to Re: Loop problem: jumps one record by johngg
in thread Loop problem: jumps one record by Anonymous Monk

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