Running a Relay

1 · What you need

• A Linux server with a public IPv4 address. The production relay is the smallest Hetzner cloud box; anything with ~512 MB of RAM is comfortable.
• One inbound UDP port (this guide uses 4001).
• Ten minutes.

2 · Install the binary

Grab the latest release binary and verify it:

curl -sLO https://github.com/alexanderwanyoike/jolt/releases/latest/download/jolt-linux-x86_64
curl -sLO https://github.com/alexanderwanyoike/jolt/releases/latest/download/jolt-linux-x86_64.sha256
sha256sum -c <(awk '{print $1"  jolt-linux-x86_64"}' jolt-linux-x86_64.sha256)
sudo install -m 755 jolt-linux-x86_64 /usr/local/bin/jolt
jolt --version

3 · A user and a data directory

The relay runs as an unprivileged user with its own state directory:

sudo useradd --system --home /var/lib/jolt-relay --shell /usr/sbin/nologin jolt
sudo mkdir -p /var/lib/jolt-relay
sudo chown jolt:jolt /var/lib/jolt-relay

4 · The systemd unit

This is the production unit, verbatim apart from the name. The flags that matter: --p2p-port 4001 fixes the port so your firewall rule and your multiaddr stay true, --no-mdns turns off LAN discovery (meaningless in a datacenter), and the API stays bound to localhost so only you can talk to it.

[Unit]
Description=Jolt relay node
Wants=network-online.target
After=network-online.target
StartLimitIntervalSec=300
StartLimitBurst=10

[Service]
Type=simple
User=jolt
Group=jolt
Environment=XDG_DATA_HOME=/var/lib/jolt-relay
WorkingDirectory=/var/lib/jolt-relay
ExecStart=/usr/local/bin/jolt start --api-bind 127.0.0.1 --api-port 9862 --p2p-port 4001 --no-mdns
Restart=on-failure
RestartSec=5s
StandardOutput=journal
StandardError=journal
LogRateLimitIntervalSec=30s
LogRateLimitBurst=1000
NoNewPrivileges=true
PrivateTmp=true
ProtectSystem=strict
ProtectHome=true
ReadWritePaths=/var/lib/jolt-relay

[Install]
WantedBy=multi-user.target

Enable and start it:

sudo systemctl daemon-reload
sudo systemctl enable --now jolt-relay.service

5 · Open the port

Only the P2P port is public. The HTTP API stays on localhost.

sudo ufw allow 4001/udp comment "Jolt relay P2P"

6 · Verify and get your relay address

The daemon's status endpoint tells you it is healthy and gives you the peer id you need:

curl -s http://127.0.0.1:9862/api/v1/status | python3 -m json.tool

Look for "peer_id". Your relay's multiaddr is:

/ip4/YOUR.SERVER.IP/udp/4001/quic-v1/p2p/YOUR_PEER_ID

7 · Point your nodes at it

On each machine that should use your relay, add it persistently:

jolt bootstrap add /ip4/YOUR.SERVER.IP/udp/4001/quic-v1/p2p/YOUR_PEER_ID
jolt bootstrap list

bootstrap list shows configured, built-in, and effective relays; adding yours does not remove the default one, so your nodes get both. For a one-off run (or to test before committing), the same multiaddr works as a start flag:

jolt start --bootstrap /ip4/YOUR.SERVER.IP/udp/4001/quic-v1/p2p/YOUR_PEER_ID

8 · Operations

• Logs: journalctl -u jolt-relay.service -f. The unit rate-limits log bursts so a chatty peer cannot fill your disk.
• Updating: stop the service before replacing the binary, then start it again. Never overwrite a running binary in place.

sudo systemctl stop jolt-relay.service
sudo install -m 755 jolt-linux-x86_64 /usr/local/bin/jolt
sudo systemctl start jolt-relay.service

• Health: the status endpoint is cheap to poll; connected_peers tells you whether anyone is using you. A relay that has just restarted takes a minute to re-establish peer connections.
• Footprint: the production relay idles at a few tens of MB of RAM and negligible CPU. Disk grows only with pinned content.

Where to go next

• The protocol series specifies what relays can and cannot see; JOLT-RFC-0001 covers resolution and JOLT-RFC-0004 covers why encrypted objects stay sealed.
• Build something on the network with the app development guide and the Jolt SDK.
• Problems? Open an issue; relay reports from real networks are exactly the feedback the project wants.