Subject: Re: [DNSOP] Some comments on draft-hoffman-dns-terminology

From: Dave Lawrence <[email-masked]>
Date: Thu, 2 Apr 2015 14:50:32 -0400

Paul Hoffman:
> I added the synonym for slave. How do people feel about "primary"
> and "master"?

Personally I'm not fond of the master/slave language and avoid the
terms.  I recognize their historic computer use and don't feel the
need to be preachy about it, but in my own speech I use
primary/secondary.

---

From: Patrik Fältström <[email-masked]>
Date: Thu, 2 Apr 2015 20:54:41 +0200

> On 2 apr 2015, at 20:50, Dave Lawrence <[email-masked]> wrote:
> 
> Paul Hoffman:

+1

   Patrik

---

From: Shumon Huque <[email-masked]>
Date: Thu, 2 Apr 2015 15:01:23 -0400

> need to be preachy about it, but in my own speech I use
Yup, me too.

Shumon.

---

From: Ted Lemon <[email-masked]>
Date: Thu, 2 Apr 2015 15:04:18 -0400

> need to be preachy about it, but in my own speech I use

Same here.   I would go a bit further and suggest that primary and secondary should be preferred.  I've suggested that to document authors in the past and haven't gotten any pushback, at least in the context of DNS primaries and secondaries.

---

From: Paul Vixie <[email-masked]>
Date: Thu, 02 Apr 2015 12:17:11 -0700

> need to be preachy about it, but in my own speech I use

i once championed the master/slave terminology but i now echo tale's
view on the matter.

-- 
Paul Vixie

---

From: "Rose, Scott W." <[email-masked]>
Date: Thu, 2 Apr 2015 15:22:50 -0400

> need to be preachy about it, but in my own speech I use
FWIW, when we were writing NIST SP 800-81 (the DNSSEC guide), we were told in the comments (can't remember the commenter) that primary/secondary should be used to denote roles, and master/slave to denote a relationship in a transfer.  Minor difference, but technically a primary could be a slave to a hidden master, secondaries could get zone data via non-AXFR means, etc.

Scott

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---

From: Paul Hoffman <[email-masked]>
Date: Thu, 2 Apr 2015 12:51:09 -0700

Given this thread, I propose the following for the draft:

Primary servers and secondary servers --- These are synonyms for "master server" and "slave server",
which were the terms used in the early DNS RFCs, and defined below. The current common usage has
shifted to "primary" and "secondary".

Slave server --- An authoritative server which uses zone transfer to retrieve the zone.
(Quoted from {{RFC1996}}, section 2.1)
{{RFC2182}} describes slave servers in detail.

Master --- Any authoritative server configured to be the source of zone transfer
for one or more slave servers. (Quoted from {{RFC1996}}, section 2.1)
{{RFC2136}} defines "master" as "an authoritative server configured to be the source of AXFR or IXFR
data for one or more slave servers".

---

From: Patrik Fältström <[email-masked]>
Date: Thu, 2 Apr 2015 22:06:26 +0200

> On 2 apr 2015, at 21:51, Paul Hoffman <[email-masked]> wrote:
> 

Well, I would change things around so that it is more clear primary and secondary are the terms to use today, like:

Primary servers and secondary servers --- These where historically named "master server" and "slave server", which were the terms used in the early DNS RFCs. The current common usage has shifted to "primary" and "secondary".

Secondary server --- An authoritative server which uses zone transfer to retrieve the zone. (See {{RFC1996}}, section 2.1) {{RFC2182}} where secondary (slave) servers are described in detail.

Primary --- Any authoritative server configured to be the source of zone transfer for one or more secondary servers. (See {{RFC1996}}, section 2.1) {{RFC2136}} where "primary" (master) servers are described as "an authoritative server configured to be the source of AXFR or IXFR data for one or more slave servers".

It should be noted that both of these are roles. For example, a server that is secondary can also act as a primary server for another secondary server.

   Patrik

---

From: Bob Harold <[email-masked]>
Date: Thu, 2 Apr 2015 16:26:41 -0400

I always thought of "primary" and "secondary" as the "old" terms used in
the BIND 4 manual, with "master" and "slave" as the new terms in the BIND 8
or 9 manuals.
For cultural reasons, I can see why some prefer primary/secondary.
master/slave is probably more accurate, and widely used in other
replication technologies.
Actually, a server can be 'master' for one zone, and 'slave' for another,
so it is zones and not servers that have the master/slave distinction.

Sorry to stir the pot.

-- 
Bob Harold
hostmaster, UMnet, ITcom
Information and Technology Services (ITS)
[email-masked]
734-647-6524 desk

On Thu, Apr 2, 2015 at 4:06 PM, Patrik Fältström <[email-masked]> wrote:

> Well, I would change things around so that it is more clear primary and
> secondary are the terms to use today, like:
>
> Primary servers and secondary servers --- These where historically named
> "master server" and "slave server", which were the terms used in the early
> DNS RFCs. The current common usage has shifted to "primary" and "secondary".
>
> Secondary server --- An authoritative server which uses zone transfer to
> retrieve the zone. (See {{RFC1996}}, section 2.1) {{RFC2182}} where
> secondary (slave) servers are described in detail.
>
> Primary --- Any authoritative server configured to be the source of zone
> transfer for one or more secondary servers. (See {{RFC1996}}, section 2.1)
> {{RFC2136}} where "primary" (master) servers are described as "an
> authoritative server configured to be the source of AXFR or IXFR data for
> one or more slave servers".
>
> It should be noted that both of these are roles. For example, a server
> that is secondary can also act as a primary server for another secondary
> server.
>
>    Patrik
>
>

---

From: Ted Lemon <[email-masked]>
Date: Thu, 2 Apr 2015 16:35:40 -0400

> FWIW, when we were writing NIST SP 800-81 (the DNSSEC guide), we were told in the comments (can't remember the commenter) that primary/secondary should be used to denote roles, and master/slave to…

That's an interesting distinction, but would be better made using different words.

---

From: Dave Lawrence <[email-masked]>
Date: Thu, 2 Apr 2015 16:39:04 -0400

Rose, Scott W. writes:
> FWIW, when we were writing NIST SP 800-81 (the DNSSEC guide), we
> were told in the comments (can't remember the commenter) that
> primary/secondary should be used to denote roles, and master/slave to
> denote a relationship in a transfer.  Minor difference, but
> technically a primary could be a slave to a hidden master, secondaries
> could get zone data via non-AXFR means, etc. 

While I don't have any trouble imagining that someone makes that
subtle distinction in much the same way my own brain has slightly
different connotations for "gray" versus "grey", I'd be surprised to
find that it is a commonly held distinction.  Of course, now that I've
said that I'm prepared for replies telling me I'm wrong, so it won't
really be a surprise then.

I don't see primary/secondary as being inviolable roles, but only in
relation to each other, much the same way as was being said above for
master/slave.  "Now the student becomes the teacher."  Just because a
nameserver is getting its data from some other doesn't mean it can't
then in turn be the primary nameserver for other secondaries.

---

From: Ted Lemon <[email-masked]>
Date: Thu, 2 Apr 2015 16:40:07 -0400

> then in turn be the primary nameserver for other secondaries.

Master and disciple?   ;)

---

From: Andrew Sullivan <[email-masked]>
Date: Thu, 2 Apr 2015 17:27:23 -0400

> the BIND 4 manual, with "master" and "slave" as the new terms in the BIND 8

I think the thing is you can have multiple masters, but for years
people referred to one of them as the "primary master" i.e. the one
you _actually_ changed before changing everything else.

I guess that has faded over time.

A

-- 
Andrew Sullivan
[email-masked]

---

From: Edward Lewis <[email-masked]>
Date: Thu, 2 Apr 2015 21:41:10 +0000

>I guess that has faded over time.

I was going to reply with something snippy on this thread, but then
reading STD 13 and RFC 5936 (AXFR) I noted that
primary/master/secondary/slave are barely mentioned at all.  Hmmmmm.
FWIW, I recall once firmly believing it was master and slave, with
"slaving a zone" being "a verb."

So I am unsure where the terms came from or how "legitimate" they are.
They certainly aren't very precise.  And as Andrew mentions, I recall
"primary master" but also the term being joked about being self-redundant.

---

From: Jim Reid <[email-masked]>
Date: Thu, 2 Apr 2015 23:36:28 +0100

> So I am unsure where the terms came from or how "legitimate" they are.

RFC1996.

---

From: Tony Finch <[email-masked]>
Date: Fri, 3 Apr 2015 00:07:16 +0100

Re. "primary", it is worth noting the definition of the SOA MNAME field in RFC 1035:

MNAME           The <domain-name> of the name server that was the original or primary source of data for this zone.

I get the impression that sometimes people regard a zone as having one primary or master and all its other servers are secondaries or slaves. But sometimes (eg when configuring slave zones in BIND) you get a per-xfer view of the terminology.

Tony.
-- 
f.anthony.n.finch  <[email-masked]>  http://dotat.at

> On 2 Apr 2015, at 20:51, Paul Hoffman <[email-masked]> wrote:
> 
> Tony.
> -- 
> f.anthony.n.finch  <[email-masked]>  http://dotat.at
> 
>

---

From: Paul Vixie <[email-masked]>
Date: Thu, 02 Apr 2015 19:38:18 -0700

Tony Finch wrote:
> MNAME           The <domain-name> of the name server that was the
>                 original or primary source of data for this zone.
>
> I get the impression that sometimes people regard a zone as having one
> primary or master and all its other servers are secondaries or slaves.
> But sometimes (eg when configuring slave zones in BIND) you get a
> per-xfer view of the terminology.

the reason RFC 1996 taxonomizes as it does is, as said up-thread, that
"primary master" means the place where non-dns data enters the dns, and
"slave" is the other servers which can also answer authoritatively for
them. but, again from RFC 1996, in a multi-layer AXFR hierarchy, some
servers will both initiate and respond to AXFR (and then later, IXFR
also) requests. therefore the terminology used to describe AXFR/IXFR
participants is in a different universe than the terminology used to
describe "where data enters the DNS" vs. "where DNS data is also
authoritatively served from."

if we were allowed to invent new terminology, i'd say:

primary, secondary, tertiary, quaternary -- assuming nobody is crazy
enough to have more than four layers

zone transfer source, zone transfer sink -- instead of "master" and "slave"

the first set describes your position in the data path. "primary" is the
from-outside-dns wormhole junction.

the second set describes your role in an AXFR/IXFR relationship. one of
them initiates notify and responds to IXFR/AXFR, the other responds to
notify and initiates IXFR/AXFR.

(and it would all have to be re-thought for what used to be called
"multi-master", anyway.)

-- 
Paul Vixie

---

From: Edward Lewis <[email-masked]>
Date: Fri, 3 Apr 2015 12:31:32 +0000

>>                 original or primary source of data for this zone.

I'm aware of this, and once even heard some folks believe the MNAME made
the SOA an implicit NS record. (Shrug.)

One of the problems in defining terms is that there are many DNS
operations practicioners, I mean staff of DNS operations, that never come
near an RFC.  And the model of operations today deviates from what was
done in the 80's.  So sometimes digging so deep...

>primary, secondary, tertiary, quaternary
>zone transfer source, zone transfer sink

FWIW, I never have been in a situation (in operations) where I'd needed to
use terms like that.  I'm not arguing over them, just saying that I've
never had to talk about "that."  We did talk about "publishers of" and
"subscribers to" a zone.

I'm not suggesting different terms.  Just pointing out that, at least in
my experience, new terminology isn't really needed for the old concepts
and digging out old meanings of terms is more to settle bar bets than to
help clarify or simplify the protocol.  I don't mean to denigrate Paul H's
effort (the individual draft) either, just expressing sympathy as he rolls
Sisyphus' ball.  After all, it is good to settle bar bets.

---

From: Casey Deccio <[email-masked]>
Date: Fri, 3 Apr 2015 13:14:28 -0400

> that is secondary can also act as a primary server for another secondary
I might propose the following, so the terms still exist in the listing, but
are simply pointers to the more current terms:

Secondary Server --- "An authoritative server which uses zone transfer to
retrieve the zone" ({{RFC1996}}, section 2.1).  {{RFC2182}} describes
secondary servers in detail.  Although early DNS RFCs (e.g., RFC1996)
referred to this as a "slave", the current common usage has shifted to
"secondary" (See, e.g., RFC2182).

Primary Server --- "Any authoritative server configured to be the source of
zone transfer for one or more [secondary] servers" ({{RFC1996}}, section
2.1), or, more specifically, "an authoritative server configured to be the
source of AXFR or IXFR data for one or more [secondary] servers" (RFC
2136).  Although early DNS RFCs (e.g., RFC1996) referred to this as a
"master", the current common usage has shifted to "primary" (See, e.g.,
RFC2182).

Master Server --- See Primary Server.

Slave Server --- See Secondary Server.

Regards,
Casey

---

From: Ralf Weber <[email-masked]>
Date: Sat, 4 Apr 2015 07:28:18 +0200

Moin!

> On 02 Apr 2015, at 22:35, Ted Lemon <[email-masked]> wrote:
> 
Yes. I used the term hidden primary in the past, and technically there would be no reason for a setup hidden primary -> primary -> secondaries, as you have two single point of failure (SPOF) there. I wouldn't deploy that. For me these words (master/primary, slave/secondary) alway have been synonyms. 

So long
Ralf

---

From: Scott Morizot <[email-masked]>
Date: Sat, 4 Apr 2015 07:29:54 -0500

On Sat, Apr 4, 2015 at 12:28 AM, Ralf Weber <[email-masked]> wrote:

> Yes. I used the term hidden primary in the past, and technically there
> would be no reason for a setup hidden primary -> primary -> secondaries, as
> you have two single point of failure (SPOF) there. I wouldn't deploy that.
> For me these words (master/primary, slave/secondary) alway have been
> synonyms.

hidden primary (with failover in place) --> signer (again with failover in
place) --> Published authoritative nameservers

Just to provide a technical context in which that configuration does make
technical sense.

Scott

---

From: Stephane Bortzmeyer <[email-masked]>
Date: Tue, 14 Apr 2015 15:41:46 +0200

On Thu, Apr 02, 2015 at 04:40:07PM -0400,
 Ted Lemon <[email-masked]> wrote 

> Master and disciple?   ;)

I asked on Twitter and got:

jedi/padawan

master/dog

---

From: Ted Lemon <[email-masked]>
Date: Tue, 14 Apr 2015 09:52:43 -0400

> master/dog

These are certainly fun, but probably don't translate as well... :)