[140791] in North American Network Operators' Group
Re: IPv6 Conventions
daemon@ATHENA.MIT.EDU (Owen DeLong)
Thu May 19 03:51:44 2011
From: Owen DeLong <owen@delong.com>
In-Reply-To: <C9704DD4-A288-4002-B552-560F97268B6B@muada.com>
Date: Thu, 19 May 2011 00:46:16 -0700
To: Iljitsch van Beijnum <iljitsch@muada.com>
Cc: NANOG list <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On May 19, 2011, at 12:05 AM, Iljitsch van Beijnum wrote:
> On 19 mei 2011, at 5:21, Owen DeLong wrote:
>=20
>>>> 2) Are we tending to use different IPs for each service on a =
device?
>=20
>>> No, the same Internet Protocol.
>=20
>> I believe he meant different IP addresses
>=20
> No, that can't be, he would have said "IP addresses".
>=20
No, it is not uncommon at least in America for people to refer to IP =
addresses by the shorter
term "IPs".
>> and I highly recommend doing so.
>=20
>> If you do so, then you can move services around and name things =
independent of
>> the actual host that they happen to be on at the moment without =
having to renumber
>> or rename.
>=20
> The DNS is already a layer of indirection so in most cases this makes =
things harder first (having to remember which address is on which host) =
so they may be easier later (not touching the DNS when services go to a =
new box). In my opinion, this isn't a good tradeoff most of the time. =
Only if you want/need addresses to be a particular way (like short for =
DNS servers) that's helpful.
>=20
We can agree to disagree. You need to remember which box your particular
services are on anyway, so, I don't see much difference there. Often, =
the time
delay in DNS changes can be a blocking factor in addressing load issues
by moving things around quickly. IP addresses can be moved with much
greater agility than the DNS abstraction because there are too many =
broken
browsers and such out there (thank you Micr0$0ft) with ridiculous =
tendencies
to cache DNS information for a very long time (well beyond the TTL).
> I was reluctant to do stateless autoconfig for servers at first but =
it's really rock solid, as long as you're reasonably sure no rogue =
router advertisements will show up on the subnet in question there's no =
reason to avoid it.
Well, there is one reason... If you have to swap a NIC or any superset =
of=20
a NIC such as an entire machine, you'll have to update
DNS. If you forget to do the DNS update in such a circumstance, you
can blackhole a lot of traffic in the time it takes to figure that out.
Owen
