diff --git a/asndb/README.md b/asndb/README.md
new file mode 100644
index 0000000..1f7c122
--- /dev/null
+++ b/asndb/README.md
@@ -0,0 +1 @@
+ASN db comes from https://iptoasn.com/
diff --git a/asndb/mkasn.pl b/asndb/mkasn.pl
new file mode 100755
index 0000000..4da440f
--- /dev/null
+++ b/asndb/mkasn.pl
@@ -0,0 +1,47 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use autodie;
+use DBI;
+
+sub fmtip($) {
+  my $ip = shift;
+  sprintf "%03d.%03d.%03d.%03d", split(/\./, $ip);
+}
+
+open(my $tsv, "<", "ip2asn-v4.tsv");
+
+my $dbh = DBI->connect("dbi:SQLite:dbname=../var/asn.db", "", "", {RaiseError => 1});
+
+$dbh->do("DROP TABLE IF EXISTS asn;");
+$dbh->do(q{CREATE TABLE asn (
+  start varchar(15) NOT NULL,
+  end   varchar(15) NOT NULL,
+  asn   INTEGER NOT NULL,
+  country TEXT,
+  desc TEXT
+);
+CREATE INDEX asn_start ON asn (start);
+CREATE INDEX asn_end ON asn (end);
+CREATE INDEX ON asn_asn ON asn (asn);});
+
+$dbh->begin_work;
+my $insert_sth = $dbh->prepare("INSERT INTO asn (start, end, asn, country, desc) VALUES (?, ?, ?, ?, ?);");
+
+while (my $line = <$tsv>) {
+  chomp $line;
+  my ($start, $end, $asn, $country, $desc) = split /\t/, $line;
+  next if $asn eq 0;
+  printf "%s - %s\n", fmtip($start), fmtip($end);
+  $insert_sth->execute(fmtip $start, fmtip $end, $asn, $country, $desc);
+}
+#$dbh->commit();
+#$dbh->begin_work();
+for my $ip (0..255) {
+  my $rv = $dbh->do("DELETE FROM asn WHERE start <= ? AND end >= ?", {}, fmtip "10.$ip.0.0", fmtip "10.$ip.0.0");
+  $rv+=$dbh->do("DELETE FROM asn WHERE start <= ? AND end >= ?", {}, fmtip "172.$ip.0.0", fmtip "172.$ip.0.0") if $ip >= 16 || $ip <= 32;
+  $rv+=$dbh->do("DELETE FROM asn WHERE start <= ? AND end >= ?", {}, fmtip "192.168.$ip.0", fmtip "192.168.$ip.0");
+  print "Removed $rv for $ip\n";
+}
+$dbh->commit();