Re: easy to remember addresses and /etc/hosts and DNS

[Alexandre Petrescu <[e-mail]>]

Le 26/04/2019 à 18:38, Kerry Lynn a écrit :
> On Fri, Apr 26, 2019 at 7:36 AM Alexandre Petrescu 
> <[e-mail] <mailto:[e-mail]>> wrote:
> 
> 
> 
>     Le 26/04/2019 à 12:05, Mark Smith a écrit :
>      > On Fri, 26 Apr 2019 at 19:54, Alexandre Petrescu
>      > <[e-mail]
>     <mailto:[e-mail]>> wrote:
>      >>
>      >>
>      >>
>      >> Le 26/04/2019 à 11:46, Mark Smith a écrit :
>      >>> On Fri, 26 Apr 2019 at 19:28, Alexandre Petrescu
>      >>> <[e-mail]
>     <mailto:[e-mail]>> wrote:
>      >>>>
>      >>>>
>      >>>>
>      >>>> Le 26/04/2019 à 06:31, Brian E Carpenter a écrit :
>      >>>>>
>      >>>>>
>      >>>>> Regards Brian Carpenter
>      >>>>>
>      >>>>> On 25-Apr-19 21:48, Philip Homburg wrote: ...
>      >>>>>> The main example you gave is somebody typing IPv6 literals while
>      >>>>>> sitting in a car.
>      >>>>>
>      >>>>> Indeed, we said from the very beginning (I mean 1994) that users
>      >>>>> should never be required to type in IPv6 addresses.
>      >>>>>
>      >>>>> Is this so hard to avoid?
>      >>>>
>      >>>> It may be easy to avoid typing IPv6 addresse when DNS was
>     available.
>      >>>>
>      >>>> But think about three cars in a covoy; the convoy is
>     disconnected from
>      >>>> the IPv6 Internet, yet fully connected on IPv6 between all
>     computers in
>      >>>> the convoy.  Which of the cars should host the DNS server?
>      >>>>
>      >>>
>      >>> All of them.
>      >>
>      >> Mark,
>      >>
>      >> Thank you very much for the suggestion.  I will consider it.
>      >>
>      >> I would like to ask you: is multicast DNS (mDNS) working on a single
>      >> subnet only?  Or does it work across subnets?
>      >>
>      >
>      > I'm not an expert in mDNS or related, have just read enough to know
>      > what problem they're solving and (very) roughly how it works.
>      >
>      > DNS Service Discovery is intended to convey that information
>     across subnets:
>      >
>      > http://www.dns-sd.org/
> 
>     I suppose DNS Service Discovery works ok on IPv6, and over multiple
>     subnets, and that it relies on the proper use of IPv6 multicast routing
>     protocols.  I never tried IPv6 multicast routing protocols on links
>     involving OCB (a kind of stripped ad-hoc WiFi at 5.9GHz).
> 
>     I suppose the use of DNS resolver address in RA is also an option in
>     this space.  I have tried this DNS-in-RA and it works ok.
> 
>     Whether DNS-in-RA, DNS-SD and mDNS should be used in cars, and how, can
>     be a subject of debate.  There is a Problem Statement draft in the
>     IPWAVE WG that lists in section "DNS Naming Service" some considered
>     problems.
> 
>     Until these things get fixed (how to use DNS in car convoy?) I need the
>     manual configuration of easy to remember link-local addresses
> 
>     When DNS works in car convoys, I expect other inconvenients using
>     name-to-address mappings compared to IP address literals.
> 
>     I might need to update the DNS servers' files with new IPv6 Link-Local
>     address to name mappings, whenever a faulty interface is replaced, or
>     when USB interface keys are moved, or when 1Gb Ethernet cards are
>     migrated to 10Gb Ethernet.
> 
>     If I am to update files, why not updating rather the computer startup
>     scripts (not DNS)?  These computer startup scripts are present in all
>     computers, including embedded, as unencumbered and open source.
> 
>     Second,
> 
>     If I use DNS names I must remember a name like:
>     front-Lead-First (means the IP address on the front bumper of the
>                         Follower, in the subnet between Lead and First
>                         Follower)
>     rear-Lead-First
>     front-First-Second
>     rear-First-Second
>     etc.
>     These names are too long to type.  So I would abbreviate them to:
>     flf
>     rlf
>     ffs
>     rfs
>     etc.
> 
>     These flf, rlf, etc are no less cryptic than a literal like
>     fe80:1::1 is.
> 
>     The short IP address literals are loved and understood by more people.
> 
>      >> (because the numerous computers in these three cars are not all on a
>      >> single subnet; they are all interconnected with IP, but there are
>      >> multiple subnets with routers in between).
>      >>
>      >
>      > There may be other options that better suit or can be better made to
>      > suit what you're trying to do, such as the work done in the
>     Homenet or
>      > the ANIMA Working Groups.
>      >
>      > Autonomic networking (the focus of ANIMA WG), sounds like it might be
>      > working on solutions to your problem domain.
>      >
>      > "Autonomic networking refers to the self-managing characteristics
>      > (configuration, protection, healing, and optimization) of distributed
>      > network elements, adapting to unpredictable changes while hiding
>      > intrinsic complexity from operators and users."
> 
>     Yes, they should be considered.
> 
>     I will make this suggestion in the IPWAVE WG for the Problem Statement
>     draft.
> 
>     Alex
> 
>      >
>      >
>      > Regards,
>      > Mark.
>      >
>      >> Alex
>      >>
>      >>>
>      >>> http://www.multicastdns.org/
>      >>>
>      >>> Multicast DNS
>      >>> https://www.ietf.org/rfc/rfc6762.txt
>      >>>
>      >>> There's also a good book on it:
>      >>>
>      >>> ""Zero Configuration Networking: The Definitive Guide
>      >>> https://www.amazon.com/gp/product/0596101007
>      >>>
>      >>>
>      >>> A number of implementations:
>      >>>
>      >>> https://www.avahi.org/ - Linux
>      >>>
>      >>> https://developer.apple.com/bonjour/ - Apple, Windows
>      >>>
>      >>> And if you want to know what inspired it,
>      >>>
>      >>> "Requirements for a Protocol to Replace the AppleTalk Name Binding
>      >>> Protocol (NBP)"
>      >>> https://tools.ietf.org/html/rfc6760
>      >>>
>      >>> This is why you need to explain your problem, not just what you
>     think
>      >>> is the solution. You'll get much quicker answers.
>      >>>
>      >>> <snip>
>      >>>
>      >
> 
> Alex,
> 
> You might want to read https://datatracker.ietf.org/wg/dnssd/about/

Noted.  I will forward this to IPWAVE WG where there is a Problem 
Statement draft under writing.

Alex

> 
> Kerry