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There are several things that are keeping IPv6 deployment from being a topic of active discussion here at my work. There are the usual technical issues, but one non-technical one appears to be a major stumbling block on the path to actually getting a deployment project going.

Addresses, memorizing of.

Specifically, IPv4 addresses are comprehensible, and IPv6 addresses just look like a big long string of hex. The human mind has real trouble memorizing lists of more than 7-8 items, and an IPv4 address (192.168.231.148) has four items in it which makes it easy for us to memorize. A fully populated IPv6 address has not only 8 sections, but each section has 4 hex digits in it. IPv6 addresses were not designed for memorization. To the technician who knows that the DNS server is at 192.168.42.42 (or more likely "42.42", since the company prefix is likely memorized), the idea of memorizing an IPv6 address fills them with dread. Which in turn makes them much less enthusiastic about participating in an IPv6 deployment project.

Because of how our network works we're not fully dynamic in terms of v4 addressing. We have several to many subnets that are entirely statically assigned for a variety of reasons, chief among them being that the overhead of static DHCP assignments is perceived as being too great. Also, some devices still aren't smart enough to pull DNS addresses out of DHCP while also having a static assignment, and therefore require manually configured DNS settings. Therefore, some v6 address memorization will have to be done.

We're not under any mandate to get v6 out the door, so we don't have pressure from the top. However, it is time to start prepping our infrastructure to handle IPv6 even if we don't convert wholesale.

For those of you who have been in IPv6-land for a while, what short-cut methods do you use to discuss or keep track of subnets and specific/critical IP addresses? If I can help reduce some of the dread surrounding IPv6 we might get the project going.

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    Oh dear...something tells me I'm hoping to retire or die before I need to troubleshoot why my freezer and refrigerator in the same appliance aren't getting the correct IP addresses so they can send "refill alerts" to Sam's Club over my wireless router. Sep 7, 2010 at 19:13
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    Note that the IETF has proposed RFC 5952 to "define a canonical textual representation format" across all systems and codes. Currently, IPv6 is difficult to parse, and the wide range of regex rules is going to leave holes in many apps. Hopefully RFC 5952 will bring some sanity to this mess. Mar 20, 2012 at 0:37
  • Note from the far distant future: 7 years later, and they're still not v6 even at the public edge.
    – sysadmin1138
    Sep 14, 2017 at 12:19

5 Answers 5

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Here are things I've noticed after working with IPv6 addresses:

  1. Don't use "full" addresses. The :: abbreviation goes a long way.
  2. Inside your organization you'll probably deal with a single prefix. This means you can all but ignore the first part of the address.
  3. Unless you're using glass teletypes copy and paste exists. Use it.
  4. As @TomTom points out, DNS exists. Use it.
  5. When you start working with v6 addresses patterns will quickly emerge. You start to recognize things like organizational prefixes (HE, Cisco, etc), Teredo, ISATAP, and stateless autoconfiguration.

IPv6 address don't have to be complex. For example, this is the address of a large company's public web server:

2001:420:80:1::5

I'm assuming the "80" is a subnet reserved for web servers. Unlike IPv4 you could also use the subnet "443" for HTTPS-only servers.

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  • But will the TCP port always be the 3rd section from the left?
    – mfinni
    Sep 8, 2010 at 20:53
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    No. That's up to the person or team who came up with the addressing plan at that organization. IPv6 gives you a lot more flexibility in that regard. Sep 9, 2010 at 15:29
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Keep them matched.

For example, as our IPv4 subnet we use 10.10.0.0/16. When I assign a IPv6 address for host 10.10.1.23 I choose 2001:0DB8::1:23.

This makes it very easy to reconstruct the v6 address during the transition or dual-stack period. In a few years, people will be used to the addressing and perhaps you'll have deployed DHCPv6 throughout.

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Why not set up a plan to assign IPs "old school"? Take your IPv6 Space make your first 4 sections kind of static and use the last four sections like you/your PHB used to:

2001:xxxx:xxxx:xxxx:192:168:42:42

It´not really a technical solution but it takes the fear factor out of the unkown a little bit.

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  • My old company did much the same thing when we moved from public to private addresses. The first two octets changed, but the last two didn't. It made the move easier on all of our brains (and documentation). If that's what we need to do for v6 to get sufficient buy-in to get going... that's an option. Kinda ugly, but an option.
    – sysadmin1138
    Sep 7, 2010 at 19:03
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    You could even go with 2001:db8:3:4:5:6:192.168.42.42 or similar, if you prefer to keep the dots in place.
    – kasperd
    Mar 13, 2015 at 14:23
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I wrote Six-N to make memorisation of key addresses easier.

http://alivate.com.au/ProductItem.aspx?ProductID=18cd7179-1e8f-45c3-93cf-345942e682c6

It was an experiment, I'm not expecting floods of support, but it's one possibility.

The crude

4FED9031E90F43FC

Becomes

ISAR SESALT JOSE HERN IS CARLE

I'll leave it to you to decide, if the latter is more memorable/communicable.

Also, it may be better, but perhaps still not useful enough. For one, there needs to be application support for it to work. For example, a powershell script so that the more memorable form can be used in real life.

Why is it more memorable?

You can read the website, but simply - there are less syllables, which are at least more resemblant to how my brain remembers things.

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I can not remember the last time I had to memorize an IP address for any server, short of creating DNS entries for public servers. Everythign is auto-assigned or set up with scripts.

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    We have enough static-addressing subnets around here that we do need to hand-set DNS addresses. Also, the older desktop techs still memorize that information even if they don't need it. DHCPv6 is definitely on the list.
    – sysadmin1138
    Sep 7, 2010 at 18:36
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    -1 Simple example: Try entering a default gateway address into a network device or configuration without using the IP address. Sep 7, 2010 at 21:43
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    Simple answer: Dont do it. Ipv6 does not require gateway preconfiguration - IP config is dynamically picked up as router announces there is a gateway available. Without router, the gateway makes no sense. So, no configuration is needed at all for gateway address changes.
    – TomTom
    Sep 7, 2010 at 23:41
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    IMHO relying on autoconf for anything on a production network is just asking for trouble. Also relying on a service that is an abstraction of lower layer information ... is also asking for trouble - this time at 3am when you are trying to troubleshoot something (like the dns servers going down)
    – Zypher
    Sep 8, 2010 at 15:50
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    Actually yes... and no. I find IPv56 autoconf very ince, except the rogue item in the network scenario, I agree. THAT SAID: use autoconf, then "Hardcode" the config with a script, finished. After the script runs, autoconf is off for a server.
    – TomTom
    Sep 9, 2010 at 9:06

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