2dust/v2rayN · warning · ApplicationException

RasEnumEntries failed with error code: {result}

Error message

RasEnumEntries failed with error code: {result}

What it means

Thrown when the RAS (Remote Access Service) RasEnumEntries call still returns a non-zero result after the buffer-retry loop. The loop grows the buffer on ERROR_BUFFER_TOO_SMALL/insufficient-buffer, but any other non-zero RAS result is treated as a hard failure.

Source

Thrown at v2rayN/ServiceLib/Handler/SysProxy/ProxySettingWindows.cs:235

            rasEntryNames = new RASENTRYNAME[bufferSize / Marshal.SizeOf(typeof(RASENTRYNAME))];
            for (var i = 0; i < rasEntryNames.Length; i++)
            {
                rasEntryNames[i].dwSize = Marshal.SizeOf(typeof(RASENTRYNAME));
            }

            result = NativeMethods.RasEnumEntries(null, null, rasEntryNames, ref bufferSize, ref entries);
        }
        if (result == 0)
        {
            var entryNames = new List<string>();
            for (var i = 0; i < entries; i++)
            {
                entryNames.Add(rasEntryNames[i].szEntryName);
            }

            return entryNames;
        }
        throw new ApplicationException($"RasEnumEntries failed with error code: {result}");
    }

    #region WinInet structures

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    public struct InternetPerConnOptionList
    {
        public int dwSize;               // size of the INTERNET_PER_CONN_OPTION_LIST struct
        public nint szConnection;         // connection name to set/query options
        public int dwOptionCount;        // number of options to set/query
        public int dwOptionError;           // on error, which option failed

        //[MarshalAs(UnmanagedType.)]
        public nint options;
    }

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    public struct InternetConnectionOption

View on GitHub (pinned to e01717d832)

Solutions

1. Decode the RAS result code (RAS error constants) to identify the cause; common non-zero values map to specific RAS errors.
2. Ensure the Telephony/RAS services are running (services.msc) on the machine.
3. Run with sufficient privileges to enumerate RAS entries.
4. If RAS is unavailable, guard the caller to skip PPPoE enumeration (this method supports PPPoE; absence of RAS is acceptable on many systems).
5. Catch ApplicationException at the call site and degrade gracefully (return empty list) when RAS is not present.

Example fix

// before - any non-zero RAS result throws
throw new ApplicationException($"RasEnumEntries failed with error code: {result}");

// after - tolerate 'no RAS / no entries' and surface actionable error otherwise
if (result == 0)
    return entryNames;
// ERROR_NO_MORE_ITEMS / RAS service absent -> no dial-up entries
return Enumerable.Empty<string>();

// Only attempt RAS enumeration on Windows where RAS is available
if (!OperatingSystem.IsWindows()) return Enumerable.Empty<string>();
// then call EnumerateRasEntries inside a try-catch

static bool RasLikelyAvailable() => OperatingSystem.IsWindows();

try
{
    var entries = ProxySettingWindows.EnumerateRasEntries();
}
catch (ApplicationException ex) when (ex.Message.Contains("RasEnumEntries"))
{
    // RAS service absent/unavailable; PPPoE enumeration not possible, degrade to empty
    return Enumerable.Empty<string>();
}

When it happens

Trigger: EnumerateRasEntries calls RasEnumEntries; after resizing the buffer for the too-small case, result is still != 0 (not success and not a buffer-too-small retry signal).

Common situations: RAS service not running or unavailable on the machine; non-Windows or a Windows edition without RAS; corrupt telephony/RAS configuration; insufficient privileges to enumerate dial-up/PPPoE entries.

Related errors

• Set Internet Proxy failed with error code: {Marshal.GetLastW

AI-assisted analysis of 2dust/v2rayN@e01717d832 (2026-08-13). Data as JSON: /api/errors/e25daf4a62aa21fd. Report an issue: GitHub.