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how to send email using MailKit in Asp.Net Core

Am not sure whether the old method of sending Mail using Mailkit is quite working with this code below
try
{
var emailMessage = new MimeMessage();
emailMessage.From.Add(new MailboxAddress(_emailConfig.SenderName, _emailConfig.SenderAddress));
emailMessage.To.Add(new MailboxAddress(email));
emailMessage.Subject = subject;
var builder = new BodyBuilder
{
HtmlBody = message
};
emailMessage.Body = builder.ToMessageBody();
using var smtp = new SmtpClient
{
ServerCertificateValidationCallback = (s, c, h, e) => true
};
smtp.AuthenticationMechanisms.Remove("XOAUTH2");
await smtp.ConnectAsync(_emailConfig.SmtpServer, Convert.ToInt32(_emailConfig.Port), false).ConfigureAwait(false);
await smtp.AuthenticateAsync(_emailConfig.Username, _emailConfig.Password).ConfigureAwait(false);
await smtp.SendAsync(emailMessage).ConfigureAwait(false);
await smtp.DisconnectAsync(true).ConfigureAwait(false);
}
catch (Exception ex)
{
throw new InvalidOperationException(ex.Message);
}
but am having exceptions if i use the code above to send email
nvalidOperationException: 534: 5.7.14 <https://accounts.google.com/signin/continue?sarp=1&scc=1&plt=AKgnsbv
5.7.14 26mzQKtlwfyEdGzHHdpi3ewWG6skAWgOBbdNNYmwzr9Sg3fGu-KixLAfODpJsVafutidE
5.7.14 8xBOp_8rNCvk9Y6iEcOkDlcZ1d-483zQ1Krw04NvqxQdq3w4iTtC8E9bL8uGprgV>
5.7.14 Please log in via your web browser and then try again.
5.7.14 Learn more at
5.7.14 https://support.google.com/mail/answer/78754 o5sm2555896wmh.8 - gsmtp
so when i changed this line of code below to use SSLS, A new error came out
await smtp.ConnectAsync(_emailConfig.SmtpServer, Convert.ToInt32(_emailConfig.Port), true).ConfigureAwait(false);
Exception returned
InvalidOperationException: An error occurred while attempting to establish an SSL or TLS connection.
This usually means that the SSL certificate presented by the server is not trusted by the system for one or more of
the following reasons:
1. The server is using a self-signed certificate which cannot be verified.
2. The local system is missing a Root or Intermediate certificate needed to verify the server's certificate.
3. A Certificate Authority CRL server for one or more of the certificates in the chain is temporarily unavailable.
4. The certificate presented by the server is expired or invalid.
Another possibility is that you are trying to connect to a port which does not support SSL/TLS.
It is also possible that the set of SSL/TLS protocols supported by the client and server do not match.
See https://github.com/jstedfast/MailKit/blob/master/FAQ.md#SslHandshakeException for possible solutions.
have searched everywhere on how to do it,even turned on my less secured app. some recommended sendGrid, i created a free account with them also,but i dont have access to the account created. Does anyone knows how to fix the code above using Mailkit

Try it like this.
using (var smtpClient = new SmtpClient())
{
smtpClient.ServerCertificateValidationCallback = (s, c, h, e) => true;
await smtpClient.ConnectAsync("host", port, false);
if (smtpClient.Capabilities.HasFlag(SmtpCapabilities.Authentication))
{
smtpClient.AuthenticationMechanisms.Remove("XOAUTH2");
await smtpClient.AuthenticateAsync(username, password);
}
await smtpClient.SendAsync(mailMsg);
smtpClient.Disconnect(true);
}

How can I get a user's IP address in C#/asp.net/MVC 5?

The following code works OK locally, but it will only get the server's IP (if I'm correct).
try
{
string externalIP;
externalIP = (new WebClient()).DownloadString("http://checkip.dyndns.org/");
externalIP = (new Regex(#"\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}"))
.Matches(externalIP)[0].ToString();
model.IpCreacion = externalIP;
}
catch { }
I can't test this right now, because the two guys at my office that can make this as a public URL for testing on a server aren't here today. The code is in the controller of the project, so it runs on the server every time a client executes the app, it's not actually the client who is getting the IP address.
How can I make the client get his IP address, instead of the server, executing the code I just showed?
If I managed to put this functionality in a view, would it work as I'm intending to?
UPDATE: I tried other methods posted as answers, like
string ip = System.Web.HttpContext.Current.Request.UserHostAddress;
and
model.IpCreacion = null;
model.IpCreacion = System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
if (string.IsNullOrEmpty(model.IpCreacion))
{
model.IpCreacion = System.Web.HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
}
but now I'm only getting ::1 as a result. Which didn't happen before, as I was getting a correct IP address.

if you want to get client ip address,visit bellow post in stackoverflow
How can I get the client's IP address in ASP.NET MVC?

That gets only IP of server, because you send the request from Web Server to checkip.dyndns.org.
To get the client IP, you need to use JavaScript and do the same thing.
$.get('http://checkip.dyndns.org/', function(data) {
console.log(data); // client IP here.
})
UPDATED:
If you need client IP Address in ASP.NET Core, you can inject this service
private IHttpContextAccessor _accessor;
And use it as
_accessor.HttpContext.Connection.RemoteIpAddress.ToString()
Or in ASP.NET Framework
Public string GetIp()
{
string ip = System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
if (string.IsNullOrEmpty(ip))
{
ip = System.Web.HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
}
return ip;
}

Public string GetIp()
{
string ip = System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
if (string.IsNullOrEmpty(ip))
{
ip = System.Web.HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
}
return ip;
}

Programmatically created web service fails on client service call

I made a console application project to host a web service programmatically, but when I try to create a client proxy to my web service and call a method on it, I get the following error:
An error occurred while making the HTTP request to
https://localhost:8000/FileRetrievalPoC. This could be due to the fact
that the server certificate is not configured properly with HTTP.SYS
in the HTTPS case. This could also be caused by a mismatch of the
security binding between the client and the server.
Its inner exception:
The underlying connection was closed: An unexpected error occurred on
a send.
Its inner exception:
Unable to read data from the transport connection: An existing
connection was forcibly closed by the remote host.
Its inner exception:
An existing connection was forcibly closed by the remote host
Program.cs:
class Program
{
static void Main(string[] args)
{
var address = "https://localhost:8000/FileRetrievalPoC";
Console.WriteLine("Starting a service at {0}...", address);
FileRetrievalService.Start(address, StoreLocation.LocalMachine, StoreName.My, "localhost");
Console.WriteLine("Service started.");
Console.WriteLine("Press Enter to create a new proxy client and call the Get method.");
Console.WriteLine("Press Escape to end the application.");
while (true)
{
var key = Console.ReadKey();
if (key.Key == ConsoleKey.Enter)
{
var proxy = FileRetrievalService.Connect(address, "localhost", "exampleUsername", "examplePassword", StoreLocation.LocalMachine, StoreName.My, "localhost");
proxy.Get(#"C:\Users\User\Desktop\Document.txt");
((IClientChannel)proxy).Close();
}
else if (key.Key == ConsoleKey.Escape)
break;
}
FileRetrievalService.Stop();
}
}
IFileRetrieval.cs:
[ServiceContract]
public interface IFileRetrieval
{
[OperationContract]
string Get(string path);
[OperationContract]
void Set(string path, string contents);
}
FileRetrievalService.cs:
class FileRetrievalService : IFileRetrieval
{
private static BasicHttpsBinding _binding = new BasicHttpsBinding()
{
Name = "FileRetrievalPoC",
HostNameComparisonMode = HostNameComparisonMode.Exact,
Security = new BasicHttpsSecurity()
{
Message = new BasicHttpMessageSecurity()
{
AlgorithmSuite = SecurityAlgorithmSuite.Basic256Sha256Rsa15,
ClientCredentialType = BasicHttpMessageCredentialType.UserName
},
Mode = BasicHttpsSecurityMode.TransportWithMessageCredential,
Transport = new HttpTransportSecurity()
{
ClientCredentialType = HttpClientCredentialType.Windows
}
},
SendTimeout = TimeSpan.FromMinutes(1),
CloseTimeout = TimeSpan.FromMinutes(1),
OpenTimeout = TimeSpan.FromMinutes(1),
ReceiveTimeout = TimeSpan.FromMinutes(1)
};
private static ChannelFactory<IFileRetrieval> _channelFactory;
private static ServiceHost _host;
public static void Start(string address, StoreLocation location, StoreName name, string subject)
{
_host = new ServiceHost(typeof(FileRetrievalService));
_host.Credentials.ServiceCertificate.SetCertificate(location, name, X509FindType.FindBySubjectName, subject);
_host.AddServiceEndpoint(typeof(IFileRetrieval), _binding, address);
_host.Open();
}
public static void Stop()
{
if (_host != null)
_host.Close();
if (_channelFactory != null)
_channelFactory.Close();
}
public static IFileRetrieval Connect(string address, string domain, string username, string password, StoreLocation location, StoreName name, string subject)
{
if (_channelFactory == null)
_channelFactory = new ChannelFactory<IFileRetrieval>(_binding, address);
_channelFactory.Credentials.ClientCertificate.SetCertificate(location, name, X509FindType.FindBySubjectName, subject);
_channelFactory.Credentials.UserName.UserName = username;
_channelFactory.Credentials.UserName.Password = password;
_channelFactory.Credentials.Windows.ClientCredential = new NetworkCredential(username, password, domain);
return _channelFactory.CreateChannel();
}
public string Get(string path)
{
throw new NotImplementedException();
}
public void Set(string path, string contents)
{
throw new NotImplementedException();
}
}
Its all done programmatically, and I've looked on Stack Overflow but couldn't find a good reason why this is happening. Does anyone know what the problem is? This source code, you can add to a new console application and run it to try it out on your local machine and see it happen for yourself. Is it the SSL certificate? If so, how can I get more verbosity for the error reason here? Its not a very helpful exception.
Edit: I think I may have missed a step here, such as using netsh to bind a certificate to my machine's port.

My issue was that I did not use netsh to bind the certificate to my machine's port. Open up an administrative command prompt and call:
netsh http add sslcert ipport=0.0.0.0:8000 appid=<A randomly generated GUID for your application> certhash=<Your localhost certificate's thumbprint from the default MY store, which is under Local Machine -> Personal, which you can get from the MMC Certificates snap-in>
The next step is to make sure its under Trusted People on the client side. At least, for me this is the case since I am using a self-signed certificate that I generated for testing purposes for localhost. So for example, if you get a certificate from Comodo or Verisign or some other CA, your certificate may not need this at all since the root CA will be trusted, usually, by default in Windows, since the root CA public certificate for these is shipped out of the box inside of the Trusted Root Certification Authorities section of the Certificates MMC snap-in.
Then, all you need to do, is make sure that your machine credentials are correct. I am using Windows authentication so it tries to assert that my credentials are valid (these are specified in my code on the call to the Connect method).
As I get older, I find I tend to answer my own questions more and more often...
Edit: You only need to use the Trusted People store for all of this. If you do want to do this, then use StoreName.TrustedPeople in my code above and in your netsh command, specify certstorename=TrustedPeople, otherwise it defaults to MY, which is the Personal store in the Certificates MMC snap-in.
Also, to delete an SSL certificate that has been bound, use netsh http delete sslcert ipport=0.0.0.0:8000
Also, my code doesn't need the client certificate to be set in order to function, so that can be removed from the Connect method. Also needs some more tightening up if any of you plan to use it in production.

C# - TLS / SSL Websockets using fleck

Im trying to make a TLS/SSL websocket connection using Fleck lib.
https://github.com/statianzo/Fleck (0.9.8.25)
now i got the server startet .
but when a client connects i get the following message.
28-02-2014 19:16:15 [Info] Server started at wss://localhost:8081
28-02-2014 19:18:51 [Debug] Client connected from 127.0.0.1:62543
28-02-2014 19:18:51 [Debug] Authenticating Secure Connection
28-02-2014 19:18:52 [Debug] 0 bytes read. Closing.
anybody got an idea of what im doing wrong ?
Browser: Chrome, version : 33.0.1750.117
// sample code.
FleckLog.Level = LogLevel.Debug;
var allSockets = new List<IWebSocketConnection>();
var server = new WebSocketServer("wss://localhost:8081");
server.Certificate = new X509Certificate2(#"CRT.pfx", "Pwd");
server.Start(socket =>
{
socket.OnOpen = () =>
{
Console.WriteLine("Open!");
allSockets.Add(socket);
};
socket.OnClose = () =>
{
Console.WriteLine("Close!");
allSockets.Remove(socket);
};
socket.OnMessage = message =>
{
foreach (var user in allSockets.ToList())
{
if(user.ConnectionInfo.Id != socket.ConnectionInfo.Id){
user.Send(message);
}
}
};
});
var input = Console.ReadLine();
while (input != "exit")
{
foreach (var socket in allSockets.ToList())
{
socket.Send(input);
}
input = Console.ReadLine();
}

Is certificate signed by a browser trusted CA? If not, the web page you are opening with Chrome has to be under HTTPS so you can be prompted to accept the certificate, otherwise the connection will fail.
If even doing that does not work, please try with WebSocketListener and tell me which error you get if any.
Some issues I found debugging WSS:
Remember to change the port number to a one different to the one you used for not secure connections. Some browsers get confused if suddenly a port becomes secure or viceversa.
Remember to use the hostname indicated in the certificate to connect and not the IP.
If you are using a self-signed certificate, use it for HTTPS so you can see the dialog for accepting that certificate. When accessing via WSS:// there is not certificate acceptance dialog, it will just fail to connect.
Try with a self-signed certificate as well and see if it works.

Web Client Exception: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel

I have a simple app that uses the C# Web Client class to download a websites HTML. This is a stripped down sample of the code I'm using:
WebClient wc = new WebClient();
wc.Headers.Add("user-agent",
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705;)");
htmlCode = wc.DownloadString("https://www.oig.hhs.gov/exclusions/exclusions_list.asp");
There seems to be an issue with the websites certificate, because I encounter this exception:
The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel." "The remote certificate is invalid according to the validation procedure.
If you copy and paste the link into a browser, it requires you to agree to the risks before allowing you to view the site. Its a government website, so I'm not worried about any viruses or anything. Is there anyway to tell the web client to bypass this issue, and continue to the site?

As far as I know this is because they use a invalid or expired SSL certificate. You can bypass (ignore) it by using:
ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) => true;
Edit 2015:
This post is getting a lot of upvotes, but I regret my answer. It may remove your error, but it won't fix the issue. Accepting any SSL certificates will leave you vulnerable for man in the middle attacks, so it's generally a very bad idea. I will leave this answer for future reference, but please take note that you should try to fix the issue at the root, namely by making sure the SSL certificate is valid.

Try this:
What you would want to do is, to install the certificate into your local machine.
The procedure if it was not in code would be to do the following:
Open Internet Explorer in Administrator mode (not Chrome).
Go to the site
Select proceed
Click the titelbar / url bar on the certificate, to view the certificate.
Click install certificate.
So you can try to have a look at these other questions and see if they help you:
How can I install a certificate into the local machine store programmatically using c#?
Install certificates in to the Windows Local user certificate store in C#
Try to install the certificate and see if you go to the url again, if it asks to proceed.
****EDIT**:
I read the site certificate, it is because there is a mismatch between the certificate and the site's url.
A simple change would be this:
htmlCode = wc.DownloadString("https://oig.hhs.gov/exclusions/exclusions_list.asp");
Just remove the www.

To go even further building off of Leon Cullens' answer I came up with the following. Like he said in his answer, this should not be something you do as a permanent solution but in a case where you are getting this error intentionally this might help you out. This should add a little more security to situations where you do not have a choice and just need it to work.
My current situation is during development purposes I needed to use a self signed certificate and not a genuine signed certificate. This of course leads to the following error...
"The underlying connection was closed: Could not establish trust
relationship for the SSL/TLS secure channel."
Here is what I did to try and make it just a little more secure and try to avoid the "middle man attacks". I tried to make this as short and simple as possible but wanted to make sure I painted the whole picture to make it easy to understand.
using System;
using System.Text;
using System.Net;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;
using System.Threading;
namespace TestSecurity
{
class TestDownload
{
private void client_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
{
//Progress in the download
}
private void client_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e)
{
//Download has completed
}
private bool client_RemoteCertificateValidation(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
if (sslPolicyErrors == SslPolicyErrors.RemoteCertificateChainErrors)
{
//Check to make sure the domain is correct
X509Certificate2 certificate_details = (X509Certificate2)certificate;
if (certificate_details.Thumbprint == "91A92CA60555DB51BEDDFE1AE4ECE54C8EBEBA97")
{
#region Fingerprint for certificate
string storedFingerprint = "" +
"42048c788db687ed84407da10f78182e3487d1fc31c07ee131151f4e19b360ad2a8c452c2e7d614a5691d5479787fe70dabd" +
"64617465732e626c75656172726f77646576656c6f706d656e742e636f6d3110300e06035504080c0747656f72676961311f" +
"301d060355040a0c16426c7565204172726f7720446576656c6f706d656e74310b3009060355040613025553312f302d0609" +
"2a864886f70d0109011620737570706f727440626c75656172726f77646576656c6f706d656e742e636f6d31123010060355" +
"04070c09436c6576656c616e64301e170d3136303232393231313733335a170d3137303232383231313733335a3081b03129" +
"302706035504030c20757064617465732e626c75656172726f77646576656c6f706d656e742e636f6d3110300e0603550408" +
"42048c788db687ed84407da10f78182e3487d1fc31c07ee131151f4e19b360ad2a8c452c2e7d614a5691d5479787fe70dabd" +
"0613025553312f302d06092a864886f70d0109011620737570706f727440626c75656172726f77646576656c6f706d656e74" +
"2e636f6d3112301006035504070c09436c6576656c616e6430820122300d06092a864886f70d01010105000382010f003082" +
"010a0282010100a1cdf5af6f1bba5cc8495d8061895f39858fde814f5581266505bf4cbe0b26506278bc247963bb7c42f0b8" +
"b00638871932ed7d0a3c6562be8e5b513f24da2768051acde875b53bf94c8ea2cec397145db206b2524c42a2019a0bfa14e2" +
"a7ef0d311235e07b7e0363345fd7f397e365c0865b1b8fa8ad7eebdc1fcdce360db04f2822438621534ae10744155a710641" +
"9a69c16745974a37c5b06917036351b92c06540a6c70aa776c143eef6f7b8ec31c0c40a9eab8a399c9065bea688ea7bd1db2" +
"30af56d2ca0f8983f9e8dacb5613755fbcd8229d7042668a9130468a7480a2afde8c18bab895472ddf1ed2c49291c04e8cc2" +
"ff24db33d231b3a2498c03a5650203010001a34d304b301d0603551d0e0416041476b5c2c82ff138b87c0e2d6c046af4c634" +
"55040a0c16426c75652048c1f54dcb82e3487d1fc31c07ee1313fba9204c7b3232ba9204c7b323a021abcbda85bfca9c9931" +
"092a864886f70d01010b050003820101001ab0dfd318cc2e93a997445d0950ffcb63544c58fe1ded6e234aa7ccdcb5c890b1" +
"61b51ae08c1f54dcb3fbeca9c9932bde91d202b89c0b6f0af1a370017fa9f6a021abcbda85bfecebebc6d6067d4dc1e51ec5" +
"02cf95867516a84f01410cf80d7af4f0d3e9a86cf7b0323dba9204c7b3232c58b2289032a12aaa1ec4f64065da8bbde4fe47" +
"42048c788db687ed84407da10f78182e3487d1fc31c07ee131151f4e19b360ad2a8c452c2e7d614a5691d5479787fe70dabd" +
"de819522bb7ef870595d9738a6acdd39b7fcf6f36948ef2b404c2b6d7ebe577555148ad90013a5c2e812b2b907c808288040" +
"0db6702407585328f7e6c84b40451384391783001174d0";
#endregion
//Use the following to get the server's fingerprint to be saved and compared against
StringBuilder hex = new StringBuilder(certificate_details.RawData.Length * 2);
foreach (byte b in certificate_details.RawData)
hex.AppendFormat("{0:x2}", b);
string serverFingerprint = hex.ToString();
if (serverFingerprint == storedFingerprint) return true;
else return false;
}
else return false;
}
else if (sslPolicyErrors == SslPolicyErrors.None)
return true;
else
return false;
}
public void TestDownload(Uri targetURL, bool useCredentials, string user, string pass)
{
WebClient client = new WebClient();
bool taskCompleted = false;
//Create the event handlers to monitor progress
client.DownloadProgressChanged += new DownloadProgressChangedEventHandler(client_DownloadProgressChanged);
client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted);
ServicePointManager.ServerCertificateValidationCallback += new RemoteCertificateValidationCallback(client_RemoteCertificateValidation);
//Resolve the host
IPHostEntry host = Dns.GetHostEntry(targetURL.Host);
IPAddress ip = (host.AddressList.Length > 0 ? host.AddressList[0] : null);
//Show the UI the resolved host
//Account for credentials
if (useCredentials)
{
NetworkCredential credentials = new NetworkCredential(
user,
pass);
client.Credentials = credentials;
}
else client.Credentials = null;
//Download file
client.DownloadDataAsync(targetURL, taskCompleted);
//Go to sleep until the file download has completed
do { Thread.Sleep(500); } while (client.IsBusy);
//File download complete
//Destory the event handlers as they are no longer needed
ServicePointManager.ServerCertificateValidationCallback -= client_RemoteCertificateValidation;
client.DownloadProgressChanged -= client_DownloadProgressChanged;
client.DownloadDataCompleted -= client_DownloadDataCompleted;
}
}
}

I had this issue with message:
Could not establish trust relationship for the SSL/TLS secure channel.
I was connecting to a web service on an Apache server using a .NET client.
This is what corrected the problem for me.
(proxy).UserAgent = "Apache-HttpClient/4.1.1 (java 1.5)";

According to this Answer, add this line before using WebClient instance:
ServicePointManager.ServerCertificateValidationCallback = new
RemoteCertificateValidationCallback(delegate { return true; });