diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..590e746
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,8 @@
+MYMETA.json
+MYMETA.yml
+Makefile
+blib/
+pm_to_blib
+t/IPv6.enabled
+t/online.enabled
+t/online.nonfatal
diff --git a/lib/Net/DNS/RR.pm b/lib/Net/DNS/RR.pm
index fb5e502..148d8e5 100644
--- a/lib/Net/DNS/RR.pm
+++ b/lib/Net/DNS/RR.pm
@@ -472,7 +472,9 @@ Resource record time to live in seconds.
 # published API.  These are required for parsing BIND zone files but
 # should not be used in other contexts.
 my %unit = ( W => 604800, D => 86400, H => 3600, M => 60, S => 1 );
-%unit = ( %unit, map /\D/ ? lc($_) : $_, %unit );
+while (my($k,$v) = each %unit) {
+	$unit{lc($k)} = $v;
+}
 
 sub ttl {
 	my ( $self, $time ) = @_;
@@ -742,6 +744,31 @@ sub _wrap {
 	return @line;
 }
 
+sub _map_name {
+	my @args = @_;
+	my %r;
+	while (my($arg, $val) = splice @args, 0, 2) {
+		unless ( $arg =~ /^\d/ ) {
+			$arg =~ s/[^A-Za-z0-9]//g;      # synthetic key
+			$r{uc $arg} = $val;
+                }
+        }
+        %r
+}
+
+sub _map_allow_num {
+	my @args = @_;
+	my %r;
+	while (my($arg, $val) = splice @args, 0, 2) {
+		unless ( $arg =~ /^\d/ ) {
+			$arg =~ s/[^A-Za-z0-9]//g;      # synthetic key
+			$r{uc $arg} = $val;
+                } else {
+			$r{"$arg"} = $val;		# also accept number
+                }
+        }
+        %r
+}
 
 ################################################################################
 
diff --git a/lib/Net/DNS/RR/CERT.pm b/lib/Net/DNS/RR/CERT.pm
index 0af5f25..18a38fd 100644
--- a/lib/Net/DNS/RR/CERT.pm
+++ b/lib/Net/DNS/RR/CERT.pm
@@ -67,17 +67,7 @@ my %certtype = (
 		);
 
 	my %algbyval = reverse @algbyname;
-
-	my $map = sub {
-		my $arg = shift;
-		unless ( $arg =~ /^\d/ ) {
-			$arg =~ s/[^A-Za-z0-9]//g;		# synthetic key
-			return uc $arg;
-		}
-		my @map = ( $arg, "$arg" => $arg );		# also accept number
-	};
-
-	my %algbyname = map &$map($_), @algbyname;
+	my %algbyname = Net::DNS::RR::_map_name(@algbyname);
 
 	sub _algbyname {
 		my $arg = shift;
diff --git a/lib/Net/DNS/RR/DNSKEY.pm b/lib/Net/DNS/RR/DNSKEY.pm
index e85c0ee..b872ee4 100644
--- a/lib/Net/DNS/RR/DNSKEY.pm
+++ b/lib/Net/DNS/RR/DNSKEY.pm
@@ -53,17 +53,7 @@ use constant BASE64 => defined eval 'require MIME::Base64';
 		);
 
 	my %algbyval = reverse @algbyname;
-
-	my $map = sub {
-		my $arg = shift;
-		unless ( $arg =~ /^\d/ ) {
-			$arg =~ s/[^A-Za-z0-9]//g;		# synthetic key
-			return uc $arg;
-		}
-		my @map = ( $arg, "$arg" => $arg );		# also accept number
-	};
-
-	my %algbyname = map &$map($_), @algbyname;
+	my %algbyname = Net::DNS::RR::_map_name(@algbyname);
 
 	sub _algbyname {
 		my $arg = shift;
diff --git a/lib/Net/DNS/RR/DS.pm b/lib/Net/DNS/RR/DS.pm
index 9c2d475..9ee7c59 100644
--- a/lib/Net/DNS/RR/DS.pm
+++ b/lib/Net/DNS/RR/DS.pm
@@ -64,17 +64,7 @@ my %digest = (
 		);
 
 	my %algbyval = reverse @algbyname;
-
-	my $map = sub {
-		my $arg = shift;
-		unless ( $arg =~ /^\d/ ) {
-			$arg =~ s/[^A-Za-z0-9]//g;		# synthetic key
-			return uc $arg;
-		}
-		my @map = ( $arg, "$arg" => $arg );		# also accept number
-	};
-
-	my %algbyname = map &$map($_), @algbyname;
+	my %algbyname = @algbyname;				# already uppercase
 
 	sub _algbyname {
 		my $arg = shift;
@@ -108,18 +98,7 @@ my %digest = (
 		);
 
 	my %digestbyval = reverse @digestbyname;
-
-	my $map = sub {
-		my $arg = shift;
-		unless ( $arg =~ /^\d/ ) {
-			$arg =~ s/[^A-Za-z0-9]//g;		# synthetic key
-			return uc $arg;
-		}
-		my @map = ( $arg, "$arg" => $arg );		# also accept number
-	};
-
-	my %digestbyname = map &$map($_), @digestbyalias, @digestbyname;
-
+	my %digestbyname = Net::DNS::RR::_map_name(@digestbyalias, @digestbyname);
 
 	sub _digestbyname {
 		my $arg = shift;
diff --git a/lib/Net/DNS/RR/NSEC3.pm b/lib/Net/DNS/RR/NSEC3.pm
index 7bc5cb4..d7d385b 100644
--- a/lib/Net/DNS/RR/NSEC3.pm
+++ b/lib/Net/DNS/RR/NSEC3.pm
@@ -37,14 +37,11 @@ my %digest = (
 		'SHA-1' => 1,					# RFC3658
 		);
 
-	my @digestbyalias = ( 'SHA' => 1 );
-
+	my @digestbyalias = ( 'SHA'  => 1,
+                              'SHA1' => 1 ); 			# internal key
 	my %digestbyval = reverse @digestbyname;
-
-	my @digestbynum = map { ( $_, 0 + $_ ) } keys %digestbyval;    # accept algorithm number
-
-	my %digestbyname = map { s /[^A-Za-z0-9]//g; $_ } @digestbyalias, @digestbyname, @digestbynum;
-
+	my @digestbynum = map { ( "$_", 0 + $_ ) } keys %digestbyval;    # accept algorithm number
+	my %digestbyname = (@digestbyalias, @digestbyname, @digestbynum);
 
 	sub _digestbyname {
 		my $name = shift;
diff --git a/lib/Net/DNS/RR/RRSIG.pm b/lib/Net/DNS/RR/RRSIG.pm
index 128db40..e1eddbd 100644
--- a/lib/Net/DNS/RR/RRSIG.pm
+++ b/lib/Net/DNS/RR/RRSIG.pm
@@ -116,17 +116,7 @@ sub _defaults {				## specify RR attribute default values
 		);
 
 	my %algbyval = reverse @algbyname;
-
-	my $map = sub {
-		my $arg = shift;
-		unless ( $arg =~ /^\d/ ) {
-			$arg =~ s/[^A-Za-z0-9]//g;		# synthetic key
-			return uc $arg;
-		}
-		my @map = ( $arg, "$arg" => $arg );		# also accept number
-	};
-
-	my %algbyname = map &$map($_), @algbyname;
+	my %algbyname = Net::DNS::RR::_map_name(@algbyname);
 
 	sub _algbyname {
 		my $arg = shift;
diff --git a/lib/Net/DNS/RR/SIG.pm b/lib/Net/DNS/RR/SIG.pm
index 9162da9..225956d 100644
--- a/lib/Net/DNS/RR/SIG.pm
+++ b/lib/Net/DNS/RR/SIG.pm
@@ -148,17 +148,7 @@ sub _defaults {				## specify RR attribute default values
 		);
 
 	my %algbyval = reverse @algbyname;
-
-	my $map = sub {
-		my $arg = shift;
-		unless ( $arg =~ /^\d/ ) {
-			$arg =~ s/[^A-Za-z0-9]//g;		# synthetic key
-			return uc $arg;
-		}
-		my @map = ( $arg, "$arg" => $arg );		# also accept number
-	};
-
-	my %algbyname = map &$map($_), @algbyname;
+	my %algbyname = Net::DNS::RR::_map_name(@algbyname);
 
 	sub _algbyname {
 		my $arg = shift;
diff --git a/lib/Net/DNS/RR/TSIG.pm b/lib/Net/DNS/RR/TSIG.pm
index 836ae49..80490d0 100644
--- a/lib/Net/DNS/RR/TSIG.pm
+++ b/lib/Net/DNS/RR/TSIG.pm
@@ -50,16 +50,10 @@ use constant TSIG => typebyname qw(TSIG);
 
 
 	my %algbyval = reverse @algbyname;
-
-	my $map = sub {
-		my $arg = shift;
-		return $arg if $arg =~ /^\d/;
-		$arg =~ s/[^A-Za-z0-9]//g;			# strip non-alphanumerics
-		uc($arg);
-	};
-
-	my @pairedval = sort ( 1 .. 254, 1 .. 254 );		# also accept number
-	my %algbyname = map &$map($_), @algbyalias, @algbyname, @pairedval;
+	my %algbyname = Net::DNS::RR::_map_name(@algbyalias, @algbyname);
+        for (1..254) {
+		$algbyname{"$_"} = $_;				# also accept numbers
+	}
 
 	sub _algbyname {
 		my $key = uc shift;				# synthetic key
@@ -535,7 +529,7 @@ sub vrfyerrstr {
 		my $private = shift;	# closure keeps private key private
 		$keyref->{key} = sub {
 			my $function = $keyref->{digest};
-			return &$function( $private, @_ );
+			return &$function( $private, @_ ) if $function;
 		};
 		return undef;
 	}
@@ -549,7 +543,7 @@ sub vrfyerrstr {
 		my $keyref = $keytable{$owner};
 		$keyref->{digest} = $self->sig_function unless $keyref->{digest};
 		my $function = $keyref->{key};
-		&$function(@_);
+		&$function(@_) if $function;
 	}
 }