quasarframework/quasar · error · Error

ERROR_NETWORK_PORT_NOT_AVAIL

ERROR_NETWORK_PORT_NOT_AVAIL

Error message

ERROR_NETWORK_PORT_NOT_AVAIL

What it means

findClosestOpenPort scans upward from the requested port to 65535 looking for a free port on the given host and throws ERROR_NETWORK_PORT_NOT_AVAIL when the entire remaining port range is exhausted. The dev server infrastructure calls it via openPort/#computeConfig to pick a port for the dev server, so this failure means no usable TCP port could be bound.

Source

Thrown at app-vite/lib/utils/net.js:50

        list.push(networkAddress.address)
      }
    }
  }

  return list
}

export async function findClosestOpenPort(port, host) {
  let portProposal = port

  do {
    if (await isPortAvailable(portProposal, host)) {
      return portProposal
    }
    portProposal++
  } while (portProposal < 65_535)

  throw new Error('ERROR_NETWORK_PORT_NOT_AVAIL')
}

export function isPortAvailable(port, host) {
  const { promise, resolve, reject } = Promise.withResolvers()

  const tester = net
    .createServer()
    .once('error', err => {
      if (err.code === 'EADDRNOTAVAIL') {
        reject(new Error('ERROR_NETWORK_ADDRESS_NOT_AVAIL'))
      } else if (err.code === 'EADDRINUSE') {
        resolve(false) // host/port in use
      } else {
        reject(err)
      }
    })
    .once('listening', () => {
      tester

View on GitHub (pinned to 4841521b5f)

Solutions

1. Check what is consuming ports with 'ss -ltn' or 'lsof -i -P -n | grep LISTEN' and kill leaked/stale processes
2. Retry on a fresh machine/container restart to release ephemeral sockets
3. Verify the host argument matches a real local interface (localhost/127.0.0.1 or the intended IP)
4. Lower the starting port (e.g. 9000 instead of 64000) so the scan has more room before 65535
5. Inspect container/CI network limits (ulimit, sysctl net.ipv4.ip_local_port_range)

Example fix

// before
const port = await openPort({ port: 65000, host: '0.0.0.0' }) // scans to 65535 quickly
// after
const port = await openPort({ port: 9000, host: 'localhost' })

const net = require('node:net')
async function portFree(port, host = 'localhost') {
  return new Promise(res => {
    const s = net.createServer()
    s.once('error', () => res(false))
    s.once('listening', () => s.close(() => res(true)))
    s.listen(port, host)
  })
}
if (!(await portFree(9000))) console.warn('port 9000 busy; pick another start port')

try {
  port = await openPort({ port, host })
} catch (err) {
  if (err.message === 'ERROR_NETWORK_PORT_NOT_AVAIL') {
    // inspect listeners / restart network stack / pick another interface
  } else throw err
}

When it happens

Trigger: Calling openPort/findClosestOpenPort with a starting portProposal such that every port from it through 65535 fails isPortAvailable (already bound, permission-restricted, or otherwise unbindable) on the target host.

Common situations: Running many dev servers simultaneously on one machine exhausting ephemeral/high ports; a misconfigured host string (e.g. wrong interface) making every bind fail; containers/CI with restricted networking; a port-scan-happy firewall or a leaked process holding thousands of sockets.

Related errors

• ERROR_NETWORK_PORT_NOT_AVAIL
• Unknown network error occurred
• ️️Setting port to closest one available: ${openPort}
• Network error encountered while following the quasar.config
• Registry responded with ${response.status}

AI-assisted analysis of quasarframework/quasar@4841521b5f (2026-08-30). Data as JSON: /api/errors/1e760dd94973ce06. Report an issue: GitHub.