use strict;
my $str = 'client @0x7f9df0e8b720 11.11.111.11#12345 (helloworld.com): query: helloworld.com IN AAAA +E(0) (11.11.11.1)';
my $regex = qr/client\s(?:\S+)\s(?<dns_request_client_ip>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}|(?:::)?(?:[a-zA-Z\d]{1,4}::?){1,7}[a-zA-Z\d]{0,4})#(?<dns_request_client_port>\d+).*\s(?<message_type>query):\s(?<dns_request_queried_domain>\S+)\s(?<dns_request_class_name>\w+)\s(?<dns_request_type_name>\w+)\s(?<dns_request_setDC>(?:\+|\-)\S*)\s\((?<dns_request_name_serverIP>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}|(?:::)?(?:[a-zA-Z\d]{1,4}::?){1,7}[a-zA-Z\d]{0,4})\)/mp;
my $subst = '';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html