c# Httpclient 请求在 Windows 10 上工作正常返回 403 forbidden on windows 7（相同的代码）

Question

var handler = new HttpClientHandler
{
    AllowAutoRedirect = false,
    AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate,
    UseCookies = true,
    CookieContainer = new CookieContainer(),
    UseProxy = false,
    SslProtocols = SslProtocols.Tls12
};

using var client = new HttpClient(handler, true)
{
    Timeout = TimeSpan.FromSeconds(15)
};

client.DefaultRequestHeaders.Add("Accept", "*/*");
client.DefaultRequestHeaders.Add("User-Agent", "API");

using var response = await client.PostAsync(websiteUrl, content, cancellationToken);

if (!response.IsSuccessStatusCode)
    return string.empty

return await response.Content.ReadAsStringAsync();

The above code works fine on any windows 10 machine I have tested it, but returns a forbidden 403 on windows 7.

Does anyone have any ideas? I have already tried UseDefaultCredentials = true on the handler's initializer but the behavior is still the same.

The content is a simple string json content .

Answer 1

The 403 may be due to Windows 7 not supporting TLS by default: How to enable TLS 1.2 on clients

Earlier versions of Windows, such as Windows 7 or Windows Server 2012, don't enable TLS 1.1 or TLS 1.2 by default for secure communications using WinHTTP.

Check and see if you can enable TLS 1.2 on the Win 7 machine. Or try removing the SSL transport all together:

SslProtocols = SslProtocols.None