connections

Use the connections { ... } block to configure the RADIUS backend server connection pool.

server "PRIMARY" {
    secret "mysecret";

    connections {
        max 10;
        min 1;
        idle-timeout 5m;
    }

    connect { protocol tls; host "primary.example.com"; port 2083; tls { ... } }
}

Parameters

max

Maximum number of backend connections Radiator may keep open to the RADIUS backend server.

Radiator reuses existing live connections as long as they can still accept more requests. New connections are opened only when no current connection can accept another request and the pool is still below this limit. This setting controls the socket pool size, not a request count: one backend socket can carry up to 256 requests in flight at the same time. This applies to UDP and TCP/TLS.

Default: 10.

min

Minimum number of connections to keep open.

Use min 1; or higher to keep warm connections ready and to enable fast skip when the pool has zero live connections. On UDP, opening a socket does not prove that the remote server is reachable, so the reachability signal is weaker than with TCP or TLS.

When min is greater than zero, Radiator opens connections to the backend server in the background immediately after startup, without blocking request processing, and keeps the pool at this floor. For TCP and TLS, this removes the first-request handshake cost and lets Radiator skip a server immediately when the pool has zero live connections. On UDP, the warm-socket part still applies, but remote reachability is learned from real requests or Status-Server checks.

Default: 0.

The RADIUS warm-pool maintainer uses fixed internal pacing:

• Connect attempt timeout: 5 seconds.
• Retry interval: 1 second between attempts when the floor is not yet met.

These values are not configurable for RADIUS backends.

Known limitation: if min is very close to max, background reconnect attempts and request-triggered growth can briefly overshoot the configured max limit during recovery. A small floor such as 1 or 2 usually works best.

idle-timeout

Maximum idle lifetime for persistent TCP and TLS backend connections.

This parameter accepts duration units. When no unit suffix is provided, the value is interpreted as seconds.

Default: none. Idle connections remain open until the server closes them.

Context

Valid inside a RADIUS backend server block and inside a radius-dns-sd server_template block.

Constraints

min must not exceed max. Configuration parsing fails if min > max.

Related

• Backend Load Balancing - Server selection, pool management, and unreachable-server detection