But I can recall ip4 addresses en mass in my head. I can't memorize ip6 addresses easily. Plus, I'd like to keep pockets of private IPs that are never accessible as routable targets.
Can you explain why I wouldn't to do this or why I should evolve my understanding of ip6 better?
IPv6 address don't have to be long or publicly routable. ULA addresses (fd00::/8) are the IPv6 analogue to RFC1918 and you could theoretically use ULA addresses as short as fd00::1, fd00::2, fd00::3, and so on. Of course if you do this you run the risk of colliding with other people, so you're encouraged to randomly generate the next 40 bits after fd, which leaves you with addresses like fd32:5e26:381d::1. That's longer than IPv4 addresses, but it's a pretty fair tradeoff to get a globally unique address.
Even non-ULA IPv6 addresses need not be long. 2600:3c00:e000:6c::1 is the address of my server over at Linode, and I don't find that bad at all.
There's no real need to memorise IP addresses, that's what DNS was made for. If your servers are on the internet at large then they probably have DNS already, and if its a local network then most operating systems will now automatically work out where machines on the .local domain are (I'll be honest, I don't fully understand how that works).
I've had only a very limited exposure to IPv6, but it seemed to me that the slogan "DNS solves it for you!" doesn't really pan out. It solves it if you're on a well-set-up network and have your DNS up and running happily, but with the ad-hoc networks my [limited] experience has seen, it hasn't been trivial. Essentially, it means you have to run an interpreter service (the DNS) to understand the network - one more bit of software to configure and troubleshoot... though to be fair, IPv4 was also quite confusing when I first started playing with it.
The word you probably wanted to use was “Zeroconf”.
“Zeroconf”¹ is a name for the sum of two interacting standards, namely mDNS”² and “DNS-SD”³. Avahi⁴ is a free software implementation (for Linux and BSD) for a service where programs can register Zeroconf services (name & port number) and have Avahi announce them on the network. The other major implementation of a daemon of this kind is from Apple, and it is called “Bonjour”⁵.
This often gets confused, so, again: Zeroconf = standard. mDNS and DNS-SD = component standards. Avahi = A specific free software implementation. Bonjour = A specific proprietary implementation.
Why does it matter if an address is public or not? Whether the address is publicly routable has nothing to do with whether the host is accessible... Or don't you have firewalls?
Can you explain why I wouldn't to do this or why I should evolve my understanding of ip6 better?