aeron-io/aeron · error · BindException

no available ports in range

Error message

no available ports in range ${lowPort} ${highPort}

What it means

allocateOpenPort scans the configured wildcard port range for a UDP channel that can be bound. If findOpenPort() returns 0, meaning no port in [lowPort, highPort] could be opened, a BindException is thrown indicating the range is exhausted.

Solutions

1. Widen the wildcard port range (e.g. '20000-40000') so more concurrent channels can bind.
2. Check with 'ss -ul' or 'netstat -ul' which processes hold the range ports and stop the conflicting process.
3. Reuse/close publications when done so bound ports are released back to the manager.
4. Give each driver instance on a host a disjoint port range.

Example fix

// before
WildcardPortManager mgr = new WildcardPortManager("20000-20010", ...);
// after
WildcardPortManager mgr = new WildcardPortManager("20000-30000", ...);

// pre-check host usage
Process p = Runtime.getRuntime().exec("ss -uln"); // confirm range ports are free before startup

try { port = portManager.allocate(...); } catch (BindException e) { log.warn("port range exhausted, widening or retrying"); /* widen range or retry after closing idle channels */ }

When it happens

Trigger: All ports in the configured range are in use (by this driver's own channels, other drivers on the same host, or other processes), or the range is too small for the number of concurrent publications/images.

Common situations: Running multiple Aeron drivers on one machine sharing the same wildcard range, long-lived applications leaking channels, or containers/NAT environments where the visible free ports differ from the configured range.

Related errors

• uses the same id as
• exceeded session limit, streamId=
• invalid port value
• :low port value must be lower than high port value
• mtuLength= > MAX_UDP_PAYLOAD_LENGTH=

AI-assisted analysis of aeron-io/aeron@6d60124e15 (2026-09-12). Data as JSON: /api/errors/13e470ee871ad2a2. Report an issue: GitHub.

Appendix: source

Thrown at aeron-driver/src/main/java/io/aeron/driver/media/WildcardPortManager.java:167

        for (int i = lowPort; i < nextPort; i++)
        {
            if (!portSet.contains(i))
            {
                return i;
            }
        }

        return 0;
    }

    private int allocateOpenPort() throws BindException
    {
        final int port = findOpenPort();

        if (0 == port)
        {
            throw new BindException("no available ports in range " + this.lowPort + " " + this.highPort);
        }

        nextPort = port + 1;
        if (nextPort > highPort)
        {
            nextPort = lowPort;
        }

        portSet.add(port);

        return port;
    }
}

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