Survey - how many people running ISP nameservers define "minimal-responses" - was Re: What is the deal on missing "Authority Section" and "additional section" from google's DNS servers?

Barry Margolin barmar at alum.mit.edu
Wed Jul 11 22:55:12 UTC 2012


In article <mailman.1317.1342033147.63724.bind-users at lists.isc.org>,
 "Michael Hoskins (michoski)" <michoski at cisco.com> wrote:

> while it's largely personal preference -- i generally like to "be
> conservative in what i send, and liberal in what i accept":
> 
> http://en.wikipedia.org/wiki/Robustness_principle

This doesn't refer to quantity, but to how strictly you should adhere to 
the specification.

> it's not violating RFCs to send the full data so it's not technically
> "wrong".  however, if sending back too much data is known to cause
> problems in some cases and can potentially be used against you...then it
> seems wise to take the minimal path.

As long as you stay under the traditional 500 byte limit, I think you're 
being conservative enough.  "Liberal" would be depending on EDNS0 
extensions.

However, I think it's reasonable to adhere to the following policy:

Caching nameserver: minimal-responses yes.  The clients of these are 
primarily stub resolvers, which probably won't cache the additional 
data, so it's a waste of bandwidth and could potentially cause problems.

Authoritative nameserver: minimal-responses no.  The clients are almost 
all caching nameservers, and they'll cache what they can.

-- 
Barry Margolin
Arlington, MA



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