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Johnathan Corgan 6a564e26ac Prepare the v0.5.0 release content 
Everything the release needs except the version number, which stays at
0.5.0-dev until the tag.

The changelog entry covers only the work that is new on this line. The
point release's forty-six entries arrived under their own heading with the
forward merge and are left alone; the twenty that remained are regrouped by
topic and eight more added for changes no entry covered. Three of those
eight matter to someone upgrading. Five root modules and four re-exports
left the public library surface and Node::connections narrowed, none of it
recorded anywhere; the entry names what to use instead and distinguishes
the removed connection-phase enum from the Noise type of the same name,
which is a different type that still exists. Tracing targets moved, so an
existing RUST_LOG filter stops matching rather than erroring. And the
handshake resend interval key no longer governs the first resend, which is
now a constant, though it still governs later ones.

Seven more entries cover the work that landed after the first content pass
was written: the experimental native datagram API, the fipsctl probe
diagnostic, per-instance transport addressing, the app-owned UDP socket
seam, and the connect, disconnect and path-MTU fixes. The four bug fixes
among them all reach the deployed line, so the release notes no longer
claim this release carries exactly one fix for a shipped bug; it carries
four.

There is no security section, because after the split every security entry
belongs to the point release. The release notes say so plainly rather than
leaving a reader upgrading across both releases to conclude this one
carries no security work.

The notes are organized by audience, since the release spans OpenWrt
routers, embedders, FreeBSD, and the existing platforms, and a single list
serves none of them. The native datagram API is given a section of its own
rather than folded into the embedding seam: it is a client-facing API
rather than a way to host a node, and its one rule with no Berkeley-socket
counterpart, that the v1 wire carries no half-close, needs to be somewhere
a client author will read it. FreeBSD is advertised as supported on x86_64
only, stated wherever the platform appears. Android is advertised as an
embedding seam and not as a supported platform: a compile-gated library
surface with no artifact and no host application guide.

The configuration table rename is carried through every shipped file that
taught the old spelling: nine documentation files, the OpenWrt sample
config and a test generator, twenty-two sites in all. Guides written this
same cycle were among them, which is how the omission was found. The
documentation that arrived with the native API was checked for the same
omission and was already clean. The compatibility tests keep the old
spelling deliberately, since they exist to test the fold.

The changelog section is the fold of master's [Unreleased], not a snapshot
of it. An earlier version of this commit took a copy that then drifted, so
each section ended up holding a bullet the other did not and re-folding
them would have picked a winner silently. Both causes were fixed on master
instead — the NixOS module had never been recorded there, and the
pre-release batch of fixes was new — so [Unreleased] is a strict superset
and this is a copy rather than a merge. [0.5.0] carries all forty-six
bullets byte for byte, [Unreleased] is empty, and [0.4.2] is untouched,
checked by hashing it against master's copy.

The BLE work landed after the content pass and gets one summary entry in
the changelog and one section in the release notes rather than nine
bullets: the ble_available gate replacing target_os = "linux",
packet-boundary recovery for stream-oriented backends, peer recognition by
node identity instead of a rotating link address, the L2CAP PSM moving
into the backend seam and onto the advertisement, the embedder-supplied
Android radio, bounded probe retry, and inbound handshakes moved off the
accept loop.

The two release-notes copies no longer share their link paths. Relative
links resolve from one directory only, so the seven written for
docs/releases/ all 404ed from the root copy. The root copy now uses paths
from the repository root and the versioned copy keeps the ../ form; both
sets were resolved against the tree. The same two links are broken the
same way in the v0.4.0 through v0.4.2 notes, left as shipped history.

The contributor tallies are re-derived against maint..HEAD rather than
adjusted: twenty commits from outside the project and 171 from me, with
Arjen at fifteen and fr34aky at two. An earlier count of twelve and 138
was carried from a measurement taken three days before this content was
written, and the BLE branch widened the gap after it. Arjen's NixOS flake
module, the UDP sin6_scope_id fix and most of the BLE rework were
uncredited, as was fr34aky's L2CAP PSM seam. They want one last re-derive
at tag time if anything lands before the tag.

A sweep of all 99 tracked markdown files against the tree corrected
fifty-three of them. Four told the reader to run a build.sh that does not
exist; the only harness builder is testing/scripts/build.sh. The BLE build
prerequisites were described as optional on the strength of a probe that
build.rs does not perform, and bluez was named a build prerequisite when
libdbus-sys asks only for libdbus-1-dev and pkg-config and bluez is the
runtime daemon. Link cost is the primary sort key in next-hop ranking, not
reserved for future use; Ethernet runs on macOS as well as Linux; the BLE
MTU is the L2CAP CoC MTU rather than a negotiated ATT_MTU; effective
Ethernet MTU is 1497; the LAN discovery subsystem is src/mdns and eight
citations still named a src/discovery that never existed here. The
connectivity states in three tutorials were invented, and their jq filters
matched nothing including healthy peers. One command filtered on a literal
fd97: address prefix, which only the first byte of fixes, so it returned
empty for all but one reader in 256 and every later step using the
variable failed silently. transports.tor.advertise_on_nostr was
undocumented despite being validated against node.rendezvous.nostr.enabled.

The transport design document gains the BLE section it never had, written
from the source: the backend cascade and its compile_error tripwire, the
platform gate, the PSM advertisement wire layout and the byte budget that
forces a 16-bit service-data key, and the probe and admission bounds.

Three source files carried the same class of staleness and are corrected
with the documentation: the OpenWrt ipk usage line and Makefile error text
both named a packaging/openwrt that does not exist, and chaos.sh parsed
--subnet without listing it.

Folded in with the content commit, having been prepared alongside it:

The three GitHub Action pins that had gone stale. Every third-party
action is pinned to a commit SHA, nothing reports that a pin has aged,
and re-resolving all ten against their tags found dorny/test-reporter@v2,
taiki-e/install-action@v2 and vmactions/freebsd-vm@v1 had moved. The
three install-action@nextest references stay unpinned, since that action
reads the tool to install from the ref name. check-action-pins.sh passes
at 75 references and all nine workflow files parse.

The lockfile refresh, which is the mutating half of the dependency sweep.
Thirty-six packages move to their latest semver-compatible versions and
every one is transitive; nothing declared in Cargo.toml changes version.
No advisory forces any of them. It was taken before the validation
battery, because a gate run against a lockfile that later moves proves
nothing about what ships.

The sha2 0.10 to 0.11, hkdf 0.12 to 0.13 and bech32 0.11 to 0.12 majors,
three of the four deferred at v0.4.0 for change surface rather than
security. All three land with no source change. sha2 and hkdf must move
together, since both depend on digest 0.11, and neither changes an
algorithm. That matters because the chaining-key KDF in the Noise
handshake is built on Hkdf::<Sha256>, where an output change would be a
wire break rather than a compile error; no known-answer vectors exist for
that path, so the wire-compatibility gate is what covers it. secp256k1
0.31 is deliberately absent, since nostr's own requirement would leave
two copies of the ECC library in the tree.

The README support matrix, rebuilt as one feature table broken out by
Linux variety. A single Linux column hid that Debian, Ubuntu, Arch and
NixOS are one glibc build differing in packaging, that OpenWrt is musl
and drops BLE, and that Android is not a daemon platform. Transport rows
sort by how many platforms carry them. A Native API row reads its
platform set from the cfg gates. The installer row becomes a package
format row naming the artifact, and only the .deb is exercised per
release.

Four changelog and release-note gaps the BLE re-walk found: a Bluetooth
LE bullet stranded inside the released 0.4.2 section, a missing Fixed
entry for the scan and probe loop counting a pool-refused connection as
an established link, the unnamed embedder call that installs an
application-owned radio, and the fact that stopping the transport now
stops scanning as well as advertising.

Three release-document gaps found walking the unsurveyed commits: the UDP
reuse-flag fix stated in the direction opposite to the one it was made,
with the silent second-daemon bind it prevents left unsaid; the corrected
native-API socket paragraph carried into both release-note copies, which
still named SOCK_SEQPACKET on FreeBSD and two kernels where three are
handled; and the coordinate-cache hardening, which shipped with no text
anywhere despite adding four operator-visible status fields. That last
entry states plainly that the checks are mitigations and not a closure,
since the coordinate is still not authenticated.

Also folded in, the documentation pass that followed the content commit:

A stage-pipeline diagram for the probe, embedded in the fipsctl
reference under the five-stage list. It draws the five stages left to
right with each stage's failure reasons below it, and the bypass that
skips both lookup stages when the coordinates are cached or the target
is a direct peer. Its branches come from the probe state machine rather
than from the report, so the path stage is drawn as the one failure that
does not stop the probe.

A rewrite of the README's "What FIPS does" section. It now opens with
what a machine running FIPS gets, rather than with the two deployment
modes, and gives the self-organizing and permissionless property its own
paragraph since it holds for both modes.

A regrouping of the README's feature list into the mesh, getting traffic
onto it, and running a node, with a bullet added for the native datagram
API, which had none despite sitting in the support matrix. The Quick
start now leads with the released packages rather than a source build.
It also fixes a real defect: the package enables fips.service and
fips-dns.service and starts neither on a fresh install, so .fips name
resolution was silently dead until the next reboot and neither page said
to start the service.

A rewrite of the release notes. They opened with seven subsections of
upgrade caveats and reached the first feature two hundred lines in; they
now open with a summary of the release and elaborate below it in the
same order. Android is stated as supported through an embedded crate
rather than as a standalone daemon, consistently across all three
documents. The OpenWrt pair is corrected: it is 802.11s between routers
with FIPS supplying encryption, authentication and routing, plus a
convention of an open !FIPS SSID a client joins over WiFi, not meshing
over a router's own radios. The probe's path output is described as the
least-common-ancestor walk, which is the worst-case fallback route
rather than the route a packet takes. Detail that did not change what a
reader does was cut from the notes and kept in the changelog.
2026-08-30 10:42:59 +00:00

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# Resolve Peer Addresses via Nostr
After
[persistent-identity](persistent-identity.md), your daemon has
a stable npub and is peered with `test-us01` over a hard-coded
UDP address (`test-us01.fips.network:2121`). That static
address works fine until `test-us01` moves to a new IP, swaps
ports, or starts publishing additional endpoints you'd want to
reach. The npub is stable; the set of network endpoints behind
it may not be.
This tutorial shows the smallest useful step toward Nostr-
mediated discovery: keep the peer entry but drop its address,
let your daemon ask public Nostr relays for the peer's current
endpoint, and verify the link still works. You will not be
publishing anything yourself yet — this is the consume-only
case.
The whole exercise should take about ten minutes.
## What you'll build
```text
┌──────────────────────────┐
│ Nostr relays │
│ relay.damus.io │
│ nos.lol │
│ offchain.pub │
└────────────▲─────────────┘
"what's test-us01's │ signed advert
current address?" │ (Kind 37195)
│ from test-us01
┌───────────────────────┐ │
│ your fips daemon │ ─────────┘
│ peers: │
│ - test-us01 npub │ ─── dial resolved UDP ──▶ test-us01
│ via_nostr: true │
└───────────────────────┘
```
You'll change two things in `/etc/fips/fips.yaml`:
- Add a `node.rendezvous.nostr` block that turns the consume-
side of Nostr discovery on.
- Edit the existing `test-us01` peer entry to drop its hard-
coded `addresses:` block and add `via_nostr: true`.
After restart, the daemon will fetch `test-us01`'s current
advert from the relays, use the endpoint listed there, and
peer normally.
## How Nostr discovery resolves an address
Every FIPS daemon with `node.rendezvous.nostr.advertise: true`
publishes a signed Nostr event (Kind 37195) listing the
transport endpoints it is willing to accept connections on.
The event is signed by the daemon's secret key, so anyone
who has the corresponding npub can verify the advert really
came from that node.
`test-us01` runs with `advertise: true`. Its current advert is
visible to any Nostr client.
> **Identity is stable; endpoints are not.** A peer's npub is
> a long-lived identifier — it is who they are. Their UDP
> address, port, or transport choice is metadata that may
> change. Nostr discovery lets you bind your peer entry to the
> npub and lets the relay tell your daemon the current
> endpoint at dial time.
There are two halves to this — consuming adverts (looking up
peers by npub) and publishing adverts (being lookup-able). This
tutorial covers only the consume half.
> **Consume vs. publish.** This tutorial enables only the
> *consume* side: your daemon queries relays to resolve peers
> by npub. It does not publish an advert of its own — others
> still cannot find you by your npub yet. The next tutorial
> (`advertise-your-node`) handles the publish side.
## Step 1: Confirm your starting state
You should currently have:
- A persistent npub from
[persistent-identity](persistent-identity.md). Confirm:
```sh
sudo fipsctl show status | grep '"npub"'
```
- A working static peering with `test-us01`. Confirm:
```sh
sudo fipsctl show peers
```
Expect `test-us01` listed with `connectivity` `connected`
and a `transport_addr` of roughly
`test-us01.fips.network:2121`.
If either of those isn't true, finish the previous two
tutorials first; the Nostr discovery layer is built on top of
that working state.
## Step 2: Enable the consume side of Nostr discovery
Open `/etc/fips/fips.yaml` and add a `rendezvous` block under
`node:`:
```yaml
node:
identity:
persistent: true
rendezvous:
nostr:
enabled: true
advertise: false
```
Two knobs, one job each:
- `enabled: true` turns on the Nostr discovery runtime — the
daemon connects to a default relay set
(`wss://relay.damus.io`, `wss://nos.lol`,
`wss://offchain.pub`) and is now able to query and consume
adverts.
- `advertise: false` keeps the publish side off. Your daemon
will not publish an advert of its own at this stage. The
default is `true`, so we are setting it explicitly to
disable advertising for this consume-only tutorial. The next
tutorial flips it back on.
If you already have a `node.discovery` block from an older release it
still parses and logs one deprecation warning naming the new table, so
nothing is broken (see
[../reference/configuration.md](../reference/configuration.md)).
## Step 3: Switch the peer entry to `via_nostr`
Find the `peers:` block you added during
[join-the-test-mesh](join-the-test-mesh.md) and change it from
this:
```yaml
peers:
- npub: "npub1qmc3cvfz0yu2hx96nq3gp55zdan2qclealn7xshgr448d3nh6lks7zel98"
alias: "test-us01"
addresses:
- transport: udp
addr: "test-us01.fips.network:2121"
connect_policy: auto_connect
```
to this:
```yaml
peers:
- npub: "npub1qmc3cvfz0yu2hx96nq3gp55zdan2qclealn7xshgr448d3nh6lks7zel98"
alias: "test-us01"
via_nostr: true
connect_policy: auto_connect
```
What changed: the `addresses:` list is gone, replaced by
`via_nostr: true`. The npub stays — it is what the daemon
matches against the advert publisher's pubkey.
Save the file.
## Step 4: Restart the daemon
```sh
sudo systemctl restart fips
sudo systemctl status fips
```
The status output should show `active (running)` within a
couple of seconds. The Nostr discovery runtime starts alongside
the rest of the daemon, fetches `test-us01`'s advert from the
default relays, and uses the endpoint listed there to dial.
The resolution itself happens at debug-log level, so you will
not see it in the default-level journal. The user-facing way to
confirm everything worked is `fipsctl show peers` in the next
step. (To watch the resolution in the journal, run the daemon
manually with `RUST_LOG=fips::nostr=debug`; not
necessary for this tutorial.)
## Step 5: Verify the resolved endpoint
```sh
sudo fipsctl show peers
```
`test-us01` should appear with `connectivity` `connected` and
a `transport_addr` reflecting the endpoint that was resolved
from the advert — `test-us01.fips.network:2121` at time of
writing. That is the same endpoint you just removed from the
config, so the field on its own does not show where the daemon
got it; the `nak` query below is what settles that.
You can confirm independently that the address came from the
advert. The advert is a public Nostr event — anyone can fetch
it. With the `nak` Nostr CLI installed:
```sh
nak req -k 37195 -d "fips-overlay-v1" \
-a 06f11c31227938ab98ba982280d2826f66a063f9efe7e342e81d6a76c677d7ed \
--limit 1 wss://relay.damus.io
```
(That hex pubkey is the same identity as
`npub1qmc3...zel98` — Nostr filters take hex.) The `content`
field of the returned event lists the `endpoints` array; one
of its entries should match what `fipsctl show peers` is
using. That is what your daemon just did, signed and verified
by the Nostr layer.
## Step 6: Confirm reachability still works
```sh
ping6 -c 4 test-us01.fips
```
Expect four replies, exactly as in
[join-the-test-mesh](join-the-test-mesh.md) (which used the
full npub form). Nothing about the data plane has changed;
only the way you discovered the endpoint to dial.
## What you've learned
- **Adverts are signed.** Every Nostr discovery advert is
signed by the publisher's secret key, so the address you
resolved through a public relay is trustworthy in the same
sense the peer's npub is.
- **`via_nostr` replaces a static address.** A peer entry
with no `addresses:` block and `via_nostr: true` directs
the daemon to look the endpoint up at dial time.
- **The relay set is small and public.** Three default
relays today; the daemon round-robins queries across them.
No central FIPS infrastructure is involved.
- **Static and Nostr can mix.** You replaced the static
address with `via_nostr` here, but you could have kept both
— when both are present, static endpoints are tried first
and Nostr-resolved endpoints are appended as a fallback.
Useful when you want a fast-path direct dial but a
resilient fallback.
## Troubleshooting
If the link does not come up:
- **No advert on the relays.** If the peer's daemon is
offline or has `advertise: false`, no advert exists for
your daemon to consume. Verify with `nak` (Step 5) — if the
query returns nothing, that is the problem and it is on the
peer's side. Re-add the static `addresses:` entry as a
fallback while you wait for the peer to come back up.
- **Relay reachability.** A `Connected to 'wss://...'` line
should appear for at least one of the three default
relays, naming the relay URL. If none do, your network may
be filtering outbound WebSocket traffic or DNS for those
hostnames. Check the journal for TLS/DNS errors.
- **Stale cache.** The daemon caches resolved endpoints
briefly. If a peer's advert changes mid-session and you
hit a stale entry, restart the daemon to force a fresh
query.
- **Persistent identity not on.** If the journal shows
`Using ephemeral identity (new keypair each start)`, the
daemon falls back to ephemeral and the consume-side may
not behave as expected. Re-check
[persistent-identity](persistent-identity.md) Step 2.
## What's next
- **Advertise your own node.**
[advertise-your-node](advertise-your-node.md) publishes your
daemon's UDP endpoint on Nostr so other operators can add
you to their `peers:` list with `via_nostr: true` and reach
you the way you just reached `test-us01`. Includes a short
final section on `udp:nat`, the best-effort hole-punching
path for nodes without a directly reachable UDP endpoint.
- **Discover peers with no prior configuration.**
[open-discovery](open-discovery.md) switches your daemon to
`policy: open` so the ambient namespace itself populates
your peer list — no static `peers:` entries required (the
static ones can stay too; the two mechanisms run in
parallel).
For the operator-style scenario reference covering all five
shapes of Nostr discovery side-by-side (consume-only,
publish-direct, publish-Tor, NAT traversal, open):
- [../how-to/enable-nostr-discovery.md](../how-to/enable-nostr-discovery.md)
— five scenarios with minimal YAML fragments.
For the design and security model:
- [../design/fips-nostr-discovery.md](../design/fips-nostr-discovery.md)
— discovery runtime architecture, advert format, threat
model.
For the wire-format details:
- [../reference/nostr-events.md](../reference/nostr-events.md)
— Kind 37195 advert format, Kind 21059 traversal signaling,
Kind 10050 inbox-relay list.
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