XX-net/XX-Net · warning

Can't found acceptable ports

Error message

Can't found acceptable ports

What it means

change_reserved_port_range() found no acceptable alternative TCP dynamic port range via search_port_range(), so it refuses to run the elevated 'netsh int ipv4 set dynamic tcp start=... num=...' command and returns None. It is a warning: nothing is modified and the caller (check_and_resolve) must handle the None result.

Source

Thrown at code/default/launcher/win_compat_suggest.py:124

        return False

    def search_port_range(self):
        port_number = 16384
        for port_start in range(10000, 45000, 5000):
            port_end = port_start + port_number
            acceptable = True
            for port in self.service_ports:
                if port_start <= port <= port_end:
                    acceptable = False
                    break

            if acceptable:
                return [port_start, port_number]

    def change_reserved_port_range(self):
        ports = self.search_port_range()
        if not ports:
            xlog.warn("Can't found acceptable ports")
            return

        exec = b"netsh"
        args = b"int ipv4 set dynamic tcp start=%d num=%d" % (ports[0], ports[1])
        import win32elevate
        win32elevate.elevateAdminRun(args, exec)

    @staticmethod
    def notify(title="Title", msg="msg"):
        import ctypes
        res = ctypes.windll.user32.MessageBoxW(None, msg, title, 1)
        # Yes:1 No:2
        return res


def get_process_list():
    process_list = []
    if os.name != "nt":

View on GitHub (pinned to cfa5bc17b6)

Solutions

  1. Run 'netsh int ipv4 show excludedportrange protocol=tcp' and inspect how much of the range is blocked; reboot can clear ephemeral Hyper-V reservations.
  2. Freeze fewer ports or shrink the number of ports search_port_range demands so a window can be found.
  3. Manually reserve a safe range with an admin shell: netsh int ipv4 set dynamic tcp start=49152 num=16384, then re-run check_and_resolve.
  4. Disable Hyper-V/WSL if its reservations are consuming the entire dynamic range.

Example fix

// before
def change_reserved_port_range(self):
    ports = self.search_port_range()
    if not ports:
        xlog.warn("Can't found acceptable ports")
        return

// after
def change_reserved_port_range(self):
    ports = self.search_port_range()
    if not ports:
        xlog.warn("Can't found acceptable ports; try shrinking port_number or freeing excluded ranges")
        return None
    return ports
Defensive patterns

Strategy: fallback

Validate before calling

ranges = subprocess.check_output(
    'netsh int ipv4 show excludedportrange protocol=tcp', shell=True)
excluded = sum(int(l.split()[1]) - int(l.split()[0])
                for l in ranges.decode(errors='ignore').splitlines()
                if len(l.split()) == 2 and l.split()[0].isdigit())
if excluded > 14000:  # nearly whole dynamic range blocked
    raise RuntimeError('Port space exhausted; reboot or disable Hyper-V reservations')

Prevention

When it happens

Trigger: Calling check_and_resolve() (or change_reserved_port_range directly) when every candidate port range either overlaps a service port or falls inside Windows excluded port ranges, so search_port_range() returns an empty list.

Common situations: Hyper-V/WSL/Docker reserving most of the dynamic port range; a machine with many excluded ranges leaving no window for the ~10k-port dynamic range; overly strict search criteria in search_port_range; service ports sitting inside every candidate window.

Related errors

AI-assisted analysis of XX-net/XX-Net@cfa5bc17b6 (2026-08-27). Data as JSON: /api/errors/0a6c050891a0d9b7. Report an issue: GitHub.