Subject: [dnsext] RFC 6195, IANA and HINFO DNS RRs

From: Mykyta Yevstifeyev <[email-masked]>
Date: Sat, 13 Aug 2011 11:54:18 +0300

Hello all,

Looking through IANA MOA (http://www.iana.org/protocols/), I've noticed 
two interesting registries: "Machine Names" and "OS Names".  For the 
first, no reference was defined, neither was the assignment policy.  The 
second listed RFC 952 as reference and FCFS (see RFC 5226) as assignment 
policy spelled out there, even though RFC 952 says nothing about 
assigning OS names and pointed to RFC 943, "Assigned Numbers".  These 
two registries were grandfathered from this series of RFCs called 
"Assigned Numbers"; however, I've recalled that there is HINFO DNS RR 
which seemed to use similar parameters.

Having looked through RFC 6195, "DNS IANA Considerations", I found 
absolutely nothing which would clarify the situation with these two 
parameters.  Section 3.3.2 of RFC 1035, though, says:

> 3.3.2. HINFO RDATA format
>
>      +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
>      /                      CPU                      /
>      +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
>      /                       OS                      /
>      +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
>
> where:
>
> CPU             A<character-string>  which specifies the CPU type.
>
> OS              A<character-string>  which specifies the operating
>                  system type.
>
> Standard values for CPU and OS can be found in [RFC-1010].
>
> HINFO records are used to acquire general information about a host.  The
> main use is for protocols such as FTP that can use special procedures
> when talking between machines or operating systems of the same type.

RFC 1010 actually contained the list of then-assigned parameters, 
pointing to RFC 810 (which had been updated by RFC 952 and also used 
these two parameters).

These two registries are still being quite obscure, you may see; so what 
I propose is to formalize the procedures for assigning the 2 identifiers 
in context of DNS HINFO resource records, writing the document updating 
RFC 6195 and 952.  So any thoughts on this?

Mykyta Yevstifeyev
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---

From: Jim Reid <[email-masked]>
Date: Sat, 13 Aug 2011 11:27:27 +0100

On 13 Aug 2011, at 09:54, Mykyta Yevstifeyev wrote:

> These two registries are still being quite obscure, you may see; so  
> what I propose is to formalize the procedures for assigning the 2  
> identifiers in context of DNS HINFO resource records, writing the  
> document updating RFC 6195 and 952.  So any thoughts on this?

Don't bother. HINFO is essentially dead. Pretty much nothing uses it.  
I doubt any software queries for HINFO records. Few zones, if any,  
publish them.

A couple of <character string>s form the RDATA for HINFO. These  
strings don't need or deserve a registry. It simply doesn't matter  
what goes into these strings provided they comply with the wire  
protocol. I am struggling to see why such a registry could be needed  
or why some application would want to care enough to check the result  
of an HINFO lookup against a list of formally registered strings.

RFC1700 was the last reference to a list of names for HINFO records.  
[Interestingly, it imposes limitations on character set and length of  
the names that do not apply to DNS <character-string>s.] That 17 year  
old list contains a remarkable list of long-dead platforms: Gould,  
Pyramid, DEC, Tops-10, SunOS, Multics, etc. I suppose that graveyard  
might have some historical curiosity. Bringing it up to date and  
maintaining it seems pointless though.

What's the use case that's provoked your interest in DNS archeology?

---

From: Peter Koch <[email-masked]>
Date: Sat, 13 Aug 2011 12:41:22 +0200

Mykyta,

> RFC 6195 and 952.  So any thoughts on this?

there is no value, operational or otherwise, in "repairing" HINFO. The use
that was once envisioned for, say, FTP, didn't take up and there is no
documented or known use case. Even where used, people have entered free
form text in both of the HINFO fields for various reasons and purposes.
Just for the record, while essentially free of usable semantics, I do
not think HINFO should be declared "Historic".

In any case, the registries you mentioned would not be "owned" by dnsext.

-Peter

---

From: Mykyta Yevstifeyev <[email-masked]>
Date: Sat, 13 Aug 2011 13:46:59 +0300

> maintaining it seems pointless though.

Well, this is quite reasonable for Machine Names (even though RFC 1700 
was published in 1994 but the registry was last updated in 2001).  OS 
Names registry is quite alive (well, if one may say like this); I see 
Windows NT 6.1 (aka Windows 7) there, and the last-updated date is 
2010.  Some entries, of course, are actually really outdated and dead, 
as eg. RiscOS or what you've mentioned.

As I've already mentioned, with respect to the Machine/CPU names, I just 
have nothing to object, really :-)

I guess the limitations of RFC 1700 were drown from RFCs 810/952, but 
I'm not sure.

> What's the use case that's provoked your interest in DNS archeology?

Frankly speaking, my motivations was "this exists".

Maybe liquidating the Machine Names registry may be an option (I still 
think OS Names is a useful thing)?

Mykyta

---

From: Mykyta Yevstifeyev <[email-masked]>
Date: Sat, 13 Aug 2011 13:53:47 +0300

13.08.2011 13:48, Patrik Faltstrom (pfaltstr) wrote:
> On 13 aug 2011, at 12:27, "Jim Reid"<[email-masked]>  wrote:
>
>> Don't bother. HINFO is essentially dead. Pretty much nothing uses it. I doubt any software queries for HINFO records. Few zones, if any, publish them.
> Instead, if new such things really are needed, use more modern mechanisms like NAPTR or URI rr types

Patrik,

I guess you refer to URI RR, which is registered as follows:

> URI          256 URI                                        [Faltstrom]

So you are indeed a right person to ask: where can I find the 
documentation for this RR?

Mykyta

> (together with definition of the service you are after).
>
>     Patrik
>
>

---

From: "Patrik Faltstrom (pfaltstr)" <[email-masked]>
Date: Sat, 13 Aug 2011 12:48:14 +0200

> Don't bother. HINFO is essentially dead. Pretty much nothing uses it. I doubt any software queries for HINFO records. Few zones, if any, publish them.

Instead, if new such things really are needed, use more modern mechanisms like NAPTR or URI rr types (together with definition of the service you are after).

   Patrik

---

From: Chris Thompson <[email-masked]>
Date: 15 Aug 2011 13:59:29 +0100

>I doubt any software queries for HINFO records. Few zones, if any,  

Some zone administrators do still publish them. Locally I found e.g.

 $ dig +short hinfo {axon,moose,navier,roof,zzz}.damtp.cam.ac.uk
 "Sun4u" "Solaris2"
 "PC" "WinXP"
 "PC" "Win7"
 "Mac" "MacOS"
 "PC" "Linux/x86"

(just a sample). But I suspect more people have found useful ways
of maltreating the poor old thing. E.g. in our own zones we have
an apex HINFO record as a version indicator, used as a prereq in
dynamic updates:

 $ dig +short hinfo cam.ac.uk
 "V1" "2011-08-15 11:59:01 UTC"

I chose HINFO because (a) it wasn't TXT (b) it displays nicely
& (c) even 21st-century-ignorant nameserver software can cope
with it.

-- 
Chris Thompson               University of Cambridge Computing Service,
Email: [email-masked]    New Museums Site, Cambridge CB2 3QH,
Phone: +44 1223 334715       United Kingdom.
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