mailing list archives
Open Resolver Dataset Update
From: Jared Mauch <jared () puck nether net>
Date: Sun, 7 Apr 2013 13:46:14 -0400
I've continued to update my dataset originally posted about two weeks ago. Please take a moment and review your CIDRs
which may be running an open resolver.
I've exposed one additional bit in the user-interface that may be helpful. Some DNS servers will respond with RCODE=0
(OK) but not provide recursion. nearly 90% of the servers in the database provide recursion.
Some raw stats are also available via the 'breakdown' link on the main site.
If you operate a DNS server, or have an internal group that does, please take a moment and review your networks.
If you email me in private from a corporate address for your ASN, I can give you access to a per-ASN report.
Due to a change in methodology, I have increased the number of servers observed from 27.2 million to 30.2 million hosts.
30269218 servers responded to our udp/53 probe
731040 servers responded from a different IP than probed
25298074 gave the 'correct' answer to my A? for the DNS name queried.
13840790 responded from a source port other than udp/53
27145699 responses had recursion-available bit set.
2761869 returned REFUSED
In addition, please do continue to deploy BCP-38 to prevent spoofing wherever possible. I know at $dayjob we have been
auditing this and increased the number of customer interfaces that can not spoof.
- Open Resolver Dataset Update Jared Mauch (Apr 07)