Files
fips/docs
Johnathan Corgan f5be8ec07d Meter established-link msg1 separately from stranger admission
The msg1 rate limiter ran before the established-peer carve-out, so a
rekey or restart msg1 arriving on an existing link was refused on
exactly the same terms as a stranger's first packet and the carve-out
below it never applied to the traffic it was written for. On a node
with many peers this refuses a large share of ordinary maintenance
traffic: a field node at roughly 245 peers refused 8753 msg1 in 25
minutes, and 159 of the 201 distinct sources were peers it already
held sessions with.

Classify the source before metering it, and give established-link msg1
its own token bucket instead of a bypass. A bypass was rejected
deliberately: the limiter is global precisely because UDP sources are
spoofable, and an established-peer exemption is by construction keyed
on source address, so metering the exempted class keeps that property
where bypassing discards it.

The bucket is derived from settings the operator already sets, burst
from max_peers and rate from max_peers, the rekey interval and the
resend budget, so raising the peer limit sizes it automatically rather
than leaving a constant nobody revisits. Both parameters can be set
explicitly; an explicit zero burst or non-positive rate is rejected at
config validation, because it would refuse every rekey msg1 from an
established peer rather than disabling the limit.

Split out the established-link test as its own predicate so the
rate-limit classifier and the accept_connections gate cannot drift,
and convert the limiter's pending slot to a guard released on drop.
The slot was previously acquired in one place and released explicitly
at eighteen exit paths; once some paths stop acquiring one, any path
that still released one would have freed a slot belonging to a
different in-flight handshake, lifting effective concurrency above the
configured maximum with no counter moving and no log firing.

The "Msg1 rate limited" line now reports which limb refused, the
pending count or the token bucket, which it did not distinguish
before.

Classification costs an O(peers) scan on every inbound msg1 including
refused ones, where the previous order refused at O(1). The scan is
only needed because addr_to_link is keyed on the unresolved dial
address; correcting that keying reduces this to a single O(1) lookup.
Recorded at the predicate.
2026-07-29 17:10:29 +00:00
..

FIPS Documentation

FIPS (Free Internetworking Peering System) is a self-organizing encrypted mesh network built on Nostr identities, capable of operating over arbitrary transports — local networks, the public internet, Tor, Bluetooth, or point-to-point links — without central infrastructure.

With FIPS, your machine becomes a node in the mesh with a self-generated cryptographic identity. There are two ways to deploy it.

As an overlay on top of existing IP networks, FIPS lets your node reach any other FIPS node wherever it sits — behind a NAT, on a different ISP, on a phone over cellular, on a laptop with only Bluetooth in range, or behind a Tor onion. The mesh forwards IPv6 traffic transparently and end-to-end encrypted, with no central VPN concentrator or coordinating server.

From the ground up over raw Ethernet, WiFi, or Bluetooth, FIPS provides a complete permissionless network without any pre-existing IP infrastructure, ISP, or DNS. Any node that joins the link gets routable IPv6 addresses, peer discovery, and a path to every other node automatically.

Either way, existing networking software runs over it unchanged: SSH, HTTP servers, file transfer, anything IPv6-native works the same way it would on a local network.

New to FIPS? Start with the Getting Started guide.

Documentation Sections

Tutorials

If you are starting from scratch and want a guided path to a working mesh, go here.

How-To Guides

If you have a specific task in mind — enabling a feature, deploying a component, diagnosing a problem — go here.

Reference

If you need to look up wire formats, configuration keys, command flags, or counter inventories, go here.

Design

If you want to understand how the mesh self-organizes, why FIPS makes the choices it does, or how the pieces fit together, go here.