DNS-OARC 24th Workshop, Buenos Aires, Presentations
OARC's Open DNSSEC Validating Resolver
7 June 2011 UPDATE: The .de zone is now fully signed and the corresponding DS Resource Record has been added to the root zone, so the testbed redirection has been removed from both resolvers.
4 October 2010 UPDATE: We have now added the .de DNSSEC Testbed to both resolvers.
How To Use ODVR
OARC is pleased to offer dual-stack (as in IPv4 and IPv6), open DNSSEC-validating resolvers ("ODVR") that anyone can use to experiment with DNSSEC. The IP addresses for ODVR nameservers are:
You might like to manually query the ODVR nameservers with a tool such as dig. Be sure to add the +dnssec option:
$ dig +dnssec @22.214.171.124 iis.se | less
The AD bit in the response flags tells you that the reply data has been validated:
;; flags: qr rd ra ad; ...
Another way to use ODVR is to place the following lines in your Unix /etc/resolv.conf file:
nameserver 126.96.36.199 nameserver 188.8.131.52
Windows users can manually set DNS servers in the Internet Protocol Properties dialog of a network connection.
Finally, the client (such as dig) that you use to test against ODVR should allow you to use this tool by specifying IPv4 or IPv6 options.
ODVR has been configured with the following list of trust anchors:
ODVR also validates against ISC's DLV registry.
OARC collects data from the ODVR nameservers and makes this data available to our members for research purposes.
These graphs, updated nightly, show the number of queries received with and without the "DO" bit set, and the number of responses sent with and without the "AD" bit set.
Frequently Anticipated Questions
Q: Does it mean all my DNS lookups are secure if I use OARC's validating resolvers?
A: No, probably not, for the following reasons:
Q: Then why are you doing this?
A: A few reasons:
Q: Can I use ODVR nameservers provide protection from Kaminsky-style spoofing attacks?
A: The answer is complicated and depends on a number of other factors. Generally, this should not be your motivation for using ODVR. If you are stuck using a DNS resolver with poor source port randomization then ODVR may make you more secure. However, a determined attacker could probably spoof answers that appear to come from the ODVR nameservers and give you bad answers.
Q: I thought open resolvers were a bad thing?
A: It's true that open resolvers are usually considered to be a problem and have been used — in combination with source address spoofing — to conduct large-scale DDoS attacks. Such attacks are made possible because (1) there are hundreds of thousands, if not millions, of open resolvers, and (2) their owners/operators are unaware of the openness. The ODVR nameservers are rate-limited and closely monitored. If we have reason to suspect abuse of the ODVR nameservers, we will act quickly to stop it. Please contact the OARC Admin if you have abuse concerns.
Q: Can DNS-OARC members have non-rate-limited access?
A: Absolutely. Write to the OARC Admin to find out how.
Submitted by admin on Sat, 2014-08-09 15:50 categories [ ]
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