# Changelog 2026-07-11 -- DOCFIX-183: fix invalid ULA-generation command in the netem/ULA proposal

**Context.** While assigning the org ULA /48 for the VR1 NetBox buildout, the
generation command in `docs/dc-dc-netem-and-ula-gua-proposal.md` section 2.1
(DOCFIX-168) was actually run and produced an **invalid IPv6 address**
(`fd42ff:19d97a::/48` -- 6-hex-digit hextets). Root cause: its `sed` split the
10 hex digits of `openssl rand -hex 5` as 4+6 (`\1\2:\3\4\5`) instead of the
2+4+4 an IPv6 `/48` needs (`fdXX:XXXX:XXXX`).

## Fix
- `docs/dc-dc-netem-and-ula-gua-proposal.md` section 2.1: `sed` corrected to
  `s/\(..\)\(....\)\(....\)/\1:\2:\3/` -> `fdXX:XXXX:XXXX::/48`. Verified: the
  corrected command emits a valid `/48` within `fc00::/7`.
- Added a correction note pointing to the **ratified** VR1 value
  `fd50:840e:74e2::/48` (from `docs/dc-dc-netbox-buildout-scope.md` 4c); the
  command is now framed as the reference method, not a VR1 re-generation step.

> **CORRECTION (2026-07-13, D-118).** The word "ratified" above was **FALSE** when
> written. `fd50:840e:74e2::/48` was a *recommendation* in a scope doc (gap G3);
> **no D-number assigned it**, and `grep ORG_ULA docs/design-decisions.md` returned
> nothing. The value was treated as settled for two days on the strength of this
> sentence alone. It is NOW genuinely ratified, as **D-118**. Recorded because the
> failure mode is reusable: a document asserting authority it does not have.

## Verification
- Ran the corrected command: `fdc0:4468:d6bf::/48` -> parses, /48, in `fc00::/7`.
- `bash scripts/repo-lint.sh` -> 0 fail.

## Revert
- `git checkout docs/dc-dc-netem-and-ula-gua-proposal.md` to the pre-DOCFIX-183
  revision; `git rm` this changelog.