In message <20090128232123.GA66921@redoubt.spodhuis.org>, Phil Pennock writes:
Sorry to follow up to myself; a few more moments reviewing before sending were warranted.
On 2009-01-28 at 15:11 -0800, Phil Pennock wrote:
I'd be perfectly happy to have X list every root server, gTLD server and ccTLD server, as a starting point, on the basis that none of those should ever be sending out RD queries,
Before I get grilled on this point: it's not strictly true, since obviously things like looking up the IPs of secondary servers to send NOTIFY requests to may use recursive DNS.
Only if you have configured a forwarder. Nameserver make non- recursive queries by default.
Okay, unless you're running a nameserver which secondaries from the gTLD/ccTLD/root servers, you have no reason to see RD packets from those servers. Hopefully that's accurate enough to appease people who'll otherwise concentrate on that point and lose sight of what I was trying to show -- that *most* people could easily make use of such an RBL, if the nameservers supported using an external file for ignoring RD queries without dropping all traffic.
As people upgrade Bind naturally, the number of reflectors that could participate in an attack would go down. Get the OS vendors to use default configs which set a Bind option to maintain the file automatically and you're getting most of the way there, by sheer number of DNS servers.
-Phil
The most common reason for recursive queries to a authoritative server is someone using dig, nslookup or similar and forgeting to disable recursion on the request. Mark -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: Mark_Andrews@isc.org