docs: record the ESH IPv6 naming scheme as a docs convention, not wire-level

Picked six hexspeak names for the ESH LANs during a wind-down moment
(FACE/B055/B105/CAFE/DEAD/BASE), then checked whether any of it could
actually land on the wire before implementing anything.

It can't, for three independent reasons: a network's only nameable slot
is its /64 prefix id, which is 2 hex digits and can't spell a 4-char
word; the gateway's own address is fixed at ::1 by the UniFi platform
with no field to override it; and UniFi has no IPv6 equivalent of
use_fixedip/fixed_ip, confirmed directly against the client schema, so
individual devices can't be pinned to a chosen v6 address either --
SLAAC devices self-assign via EUI-64 or privacy extension.

So this stays a documentation mnemonic. Recorded as such rather than
implied as something live, since I'd already started suggesting a
static-camera-assignment plan that the schema check ruled out.

persistent-memory.md

@@ -127,6 +127,8 @@ _As of 2026-08-18 — **gen seat SWAPPED to `absolute-heresy` and operator-confi
 
 - **EVIDENCE HOLD (partial):** WT #394 FILE half STILL STANDS — do NOT delete on-disk gen dirs (`fiction/rex390-dcc`, `rex392-dcc`, `b59c147c5ce0`); rex393-fiction-* + r42-gate-* KEEP.
 
+- **🟡 ESH IPv6 LAN naming — a DOCS CONVENTION ONLY, not wire-level.** Fun hexspeak names picked 2026-08-18 for the six ESH LANs: `esh-cameras`=FACE, `esh-mgmt`=B055(boss), `esh-server`=B105(bios), `esh-userland`=CAFE, `esh-iot`=DEAD, Default=BA5E(base). **Investigated and confirmed these CANNOT be made literal on the wire**: (1) a network's only nameable slot is its `/64` subnet id (`ipv6_pd_prefixid`), which is 2 hex digits (0-255) — not enough room to spell a 4-char word; (2) the gateway's own address is fixed at `::1` by the UniFi platform, no field to customize it (`ipv6_aliases` exists but schema unknown, not attempted blind); (3) UniFi has **no IPv6 equivalent of `use_fixedip`/`fixed_ip`** (checked the client schema directly) — individual devices cannot be pinned to a chosen v6 address the way v4 static reservations work; SLAAC devices self-assign via EUI-64 (MAC-derived, stable) or privacy-extension (random, rotates). So the names are a mnemonic for humans/docs, not something that will ever appear in a `dig`/`ip -6` output. Only `esh-cameras` has v6 live at all (`2607:73c0:402:1d00::/64`, PD from the ESH `/56`); the other five stay `ipv6_interface_type: none` pending a firewall-policy pass before enabling SLAAC fleet-wide (LAN devices would get globally reachable addresses).
+
 - **🟢 ESH↔colo IPsec FIXED 2026-08-18 — dialup + NAT-T.** Broke when ESH lost its public IP (Cox unplugged for the fiber install; 5G handed out RFC1918 `192.168.200.111`). **TWO causes:** phase1 `ana-to-eshudm` was `type static` pinned to the dead `70.181.90.232`, AND **`nattraversal disable`** — so even re-pinning the IP would have failed, since ESP cannot cross NAT without UDP-4500. `pfi-ana-nh3` survived only because NH3 is publicly addressed. ⚠ **FortiOS REFUSES `set type dynamic` on an existing tunnel** ("Cannot change tunnel type once configured", clean rollback). **Fix = ADDITIVE, not a recreate:** new phase1+phase2 **`ana-eshudm-dyn`** (`type dynamic`, ikev2, aes256-sha1, dh14, NAT-T default on, PSK read from the ESH UDM API), static route id **10** (`dstaddr ana-to-eshudm_remote` → `device ana-eshudm-dyn`, distance 20), policies **73/74** (consolidated multi-zone in/out). Old `ana-to-eshudm` LEFT IN PLACE, dead and harmless, as rollback. Verified: `ana-eshudm-dyn_0 97.170.236.56:4500 selectors 1/1` (`_0`=dialup child, `:4500`=NAT-T, carrier IP), ESH→colo all hosts 40-56ms, colo→ESH OK, traceroute now 3 hops encapsulated vs 8 leaking to the carrier. FortiGate config backed up first at `nh3-dev:~/backups/ana-gw/` (1.17MB, 36903 lines). ⚠ **RESIDUAL: the UDM's `ipsec_local_ip` needs a LITERAL IP** (empty rejected `api.err.InvalidPayload`) — currently `192.168.200.111`, so **it must be updated again when the fiber lands** or the tunnel drops. Gateway end is address-agnostic now; UniFi end is not — **it will drop on ANY ESH WAN change: Cox reclaiming WAN1 (still `failover_priority=1`), the fiber cutover, or a DHCP renewal.** **MANUAL FIX (seconds):** read the UDM's live `wan_ip` from `/stat/health` and PUT it into `esh-ana.ipsec_local_ip` via `rest/networkconf/<id>` using `unifi/esh-udmpm-api-key`. A self-healing watcher is **PARKED (`self-healing-ipsec-local-ip-watcher-for-the-esh`), trigger = once the new ESH fiber is live and its addressing has settled** — operator's call 2026-08-18, deliberately not built now because it would target an address that is about to change. Park item also carries the follow-up to delete the old `ana-to-eshudm` tunnel, whose distance-10 route would silently reclaim traffic if Cox ever returns on `70.181.90.232`.
 
 - **🟡 FLEET IPv6 — STILL JUSTIFIED, but the REASON was wrong and is now corrected (2026-08-18).** There are TWO inter-site links with OPPOSITE NAT behaviour, and the original note conflated them. **(a) NH3↔ESH = Site Magic = WireGuard — SURVIVES arbitrary NAT, PROVEN.** During the fiber cutover ESH failed over to 5G on `192.168.200.111` (**RFC1918 double-NAT, zero inbound path, strictly worse than CGNAT**) and it held: nh3-dev/nh3-docker reachable ~40-43ms, ssh+exec fine. Mechanism: `magic_site_to_site_vpn` on-device is only `enabled`+keypair (**no WAN binding — it rides whichever uplink is active**), and **NH3's edge is public at `70.230.226.88`**, so the NAT'd side dials out and never needs reachability. **(b) colo(Anaheim)↔ESH = IPsec on the ana-gw FortiGate — BROKEN RIGHT NOW under those same conditions.** ana-docker/pfi-pve/pbs-ana ALL FAIL from esh-pve-nas; traceroute shows 10.250.x packets leaving the UDM to the 5G modem `192.168.200.99`, then wandering the carrier (`10.180.141.194`, `172.19.3.14`) and dying — **not encapsulated at all**, so no SA is up and traffic falls to the default route. Site-to-site IPsec pins a peer IP; ESH no longer has a routable one. **⇒ IPv6 keeps its justification, on the IPsec link SPECIFICALLY.** ⚠ An earlier version of this entry claimed the premise was refuted outright — that over-generalised a WireGuard result onto an IPsec link. **Operator caught it.** See ops-lessons-playbook §8. State: **NH3 WAN live** (`2600:1700:b25:c110::48`, AT&T delegates exactly **one /64**), **colo none** (FortiGate has zero v6), **ESH none** (both WANs `wan_type_v6=disabled`). NH3 LANs all reverted to `ipv6_interface_type=none` per operator. Work when addresses land: v6 on `ana-wg` eth0 + a **v6 port-forward for UDP 31337** on the FortiGate (its WG socket is already dual-stack — no WG reconfig), flip the UDM WG server off `v4`-pinned binding, and **AAAA records** so the dynamic prefixes at all three sites don't break endpoints. Full detail + access recipes → `persistent-memory.d/2026-08-17-fleet-ipv6-mesh.md`.