Default Relay Configurations for Iroh: Ports, Maps, and Client Settings

Iroh provides built-in default relay configurations including QUIC port 7842, production relays across four global regions, and staging endpoints for testing, all defined in the iroh and iroh-relay crates.

The n0-computer/iroh repository ships with carefully chosen default relay configurations that dictate how the Relay server exposes endpoints and how clients discover them. These defaults cover everything from network ports and cache limits to hard-coded production hostnames for North America, Europe, and Asia-Pacific regions.

Default Relay Server Ports and Limits

The core numeric defaults are defined in iroh-relay/src/defaults.rs. These constants control how the relay server binds to network interfaces and manages internal resources.

Network Ports

Iroh uses the following default ports for relay operations:

• QUIC port: 7842 (chosen because the digits spell "QUIC" on a telephone keypad)
• HTTP port: 80
• HTTPS port: 443
• Metrics port: 9090

These values are exported as constants like DEFAULT_RELAY_QUIC_PORT from the iroh-relay crate and re-exported in iroh/src/defaults.rs.

Cache and Timeout Settings

Beyond ports, the defaults include resource limits and timing parameters:

• Key-cache capacity: 1,048,576 entries (approximately 56 MiB)
• Dial timeout: 1.5 seconds
• Happy-Eyeballs delay: 250 milliseconds
• DNS timeout: 3 seconds

These settings are defined in iroh-relay/src/defaults.rs between lines 18 and 48.

Production Relay Map

For client connectivity, Iroh defines a production relay map spanning four global regions. These hostnames are hard-coded constants in iroh/src/defaults.rs and resolve to HTTPS endpoints.

The production regions include:

• NA-East: use1-1.relay.n0.iroh.link.
• NA-West: usw1-1.relay.n0.iroh.link.
• EU: euc1-1.relay.n0.iroh.link.
• AP: aps1-1.relay.n0.iroh.link.

The default_relay_map() function constructs a RelayMap containing a RelayConfig for each endpoint:

use iroh::defaults::prod;

let relay_map = prod::default_relay_map();

Each region-specific helper function (such as default_na_east_relay()) builds the configuration from a URL formatted as https://{hostname}/.

Staging Relay Map

For integration testing, Iroh provides a reduced staging relay map that uses only the NA-East and EU regions with separate staging hostnames:

• NA-East Staging: use1-1.staging-relay.n0.iroh.link.
• EU Staging: euc1-1.staging-relay.n0.iroh.link.

Access this map via the staging module:

use iroh::defaults::staging;

let staging_map = staging::default_relay_map();

Using Default Configurations in Code

You can access these defaults programmatically to customize client behavior or configure custom relay servers.

Retrieve a Specific Region

To get a single relay configuration for a specific region:

use iroh::defaults::prod;

let eu_cfg = prod::default_eu_relay();
println!("EU relay URL: {}", eu_cfg.url());

Override Server Defaults

When building a custom relay server, import constants from iroh-relay:

use iroh_relay::defaults::DEFAULT_RELAY_QUIC_PORT;

let quic_port = DEFAULT_RELAY_QUIC_PORT; // 7842

Switch to Staging for Testing

For test environments, replace the production map with the staging map:

use iroh::defaults::staging;

let staging_map = staging::default_relay_map();
// Use with client API: iroh::client::Builder::with_relay_map(staging_map)

Summary

• Default ports: QUIC uses 7842, HTTP uses 80, HTTPS uses 443, and metrics use 9090.
• Production relays: Four regions (NA-East, NA-West, EU, AP) with hostnames ending in relay.n0.iroh.link..
• Staging relays: Two regions (NA-East, EU) with hostnames ending in staging-relay.n0.iroh.link..
• Key files: iroh-relay/src/defaults.rs defines numeric constants, while iroh/src/defaults.rs defines relay maps and hostnames.
• Access patterns: Use prod::default_relay_map() for production or staging::default_relay_map() for testing.

Frequently Asked Questions

What is the default QUIC port for Iroh relays?

The default QUIC port is 7842, chosen because the digits spell "QUIC" on a telephone keypad. This constant is defined in iroh-relay/src/defaults.rs and re-exported as DEFAULT_RELAY_QUIC_PORT.

How do I switch from production to staging relays in Iroh?

Import from iroh::defaults::staging instead of iroh::defaults::prod and call staging::default_relay_map(). This returns a RelayMap containing only the NA-East and EU staging endpoints for safe integration testing.

What is the default key-cache capacity for relay servers?

The default key-cache capacity is 1,048,576 entries, which consumes approximately 56 MiB of memory. This limit is defined in iroh-relay/src/defaults.rs to balance performance against resource usage.

Where are the default relay hostnames defined in the source code?

Production hostnames are defined in iroh/src/defaults.rs as constants like NA_EAST_RELAY_HOSTNAME and EU_RELAY_HOSTNAME. The iroh-relay/src/defaults.rs file contains only the numeric defaults such as ports and timeouts.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}