Delivery of non-cached replies

[Sam Trenholme]

> I also used it to created an ASCII
> version under http://jblomer.web.cern.ch/jblomer/dns-nxdomain.txt.

Which has this in the information:

Domain Name System (response)
    [Request In: 1]
    [Time: 0.026233000 seconds]
    Transaction ID: 0xb02c
    Flags: 0x8403 (Standard query response, No such name)
        1... .... .... .... = Response: Message is a response
        .000 0... .... .... = Opcode: Standard query (0)
        .... .1.. .... .... = Authoritative: Server is an authority for domain
        .... ..0. .... .... = Truncated: Message is not truncated
        .... ...0 .... .... = Recursion desired: Don't do query recursively
        .... .... 0... .... = Recursion available: Server can't do
recursive queries
        .... .... .0.. .... = Z: reserved (0)
        .... .... ..0. .... = Answer authenticated: Answer/authority
portion was not authenticated by the server
        .... .... .... 0011 = Reply code: No such name (3)
    Questions: 1
    Answer RRs: 0
    Authority RRs: 0
    Additional RRs: 0

This is an unusual packet; usually, there's a SOA packet in the
"Authority" (NS) section of the reply.

> The patch fixes the problem for me.

Excellent.  I have applied the patch, and have a new snapshot of the
stable version of Deadwood available here:

> I am not familiar enough with DNS to tell for sure, but I could imagine
> that the reply from the upstream DNS server is just broken enough not to
> be accepted by Deadwood.

Exactly.  Negative answers should have a SOA in the NS part of the
reply.  A negative response without a NS in the reply is actually
something I haven't seen before; the code has been updated to handle
these better (thanks for the patch!).

> I attached another version of the path according to your coding style
> comments (but still without touching the documentation).  The default
> value is not to change the current behaviour.

The current snapshot has the behavior enabled by default.  I have also
documented the parameter.  To look at this code, go here:

http://www.maradns.org/deadwood/snap/

And download the .tar.bz2 file with today's snapshot (20091021).

As an aside, would it be OK for me to put on my resume that CERN uses MaraDNS?

Next: Forward-port the patch to the "head" (2.4) branch of Deadwood.

- Sam