use strict;
use warnings;
my $ip = "";

while (<>) {
    if (/Relay.access.denied/) {
        my $rec;

        do {
            $rec = <>;
            print "$2\n" if $rec =~ /(\d+)\s+(\S+)/;
            $ip = $2;
        } until ($rec !~ /(\d+)\s+(\S+)/);
    }
}