Unable to connect to MongoDB server using x509 certificate authentication from c# - mongodb

Question

I have configured MongoDB server as given in document https://docs.mongodb.com/manual/core/security-x.509/
and I connected using mongo shell it is working fine.
Next I tried to connect to same server form c# driver, but Time out exception raised.
Below is my code
var cert = new X509Certificate2(#"C:\Program Files\MongoDB\Server\3.2\ssl\client.pfx", "secretkey");
var sslcrd = MongoCredential.CreateMongoX509Credential("CN=Client1,O=School,ST=Some-State,C=IN");
settings.SslSettings = new SslSettings() ;
settings.UseSsl = true;
settings.SslSettings.ClientCertificates = new List<X509Certificate>()
{
cert
};
settings.SslSettings.EnabledSslProtocols = SslProtocols.Default;
settings.SslSettings.ClientCertificateSelectionCallback =
(sender, host, certificates, certificate, issuers) => settings.SslSettings.ClientCertificates.ToList()[0];
settings.SslSettings.ServerCertificateValidationCallback = (sender, certificate, chain, errors) => true;
settings.SslSettings.CheckCertificateRevocation = false;
settings.VerifySslCertificate = false;
settings.Credentials = new[] { sslcrd };
MongoClient client = new MongoClient(settings);
var db = client.ListDatabases().ToList();
I went through MongoDB server logs and I am able to see below error
2017-04-10T11:18:21.559+0530 I NETWORK [initandlisten] connection
accepted from
127.0.0.1:53901 #64 (1 connection now open) 2017-04-10T11:18:21.559+0530 E NETWORK [conn64] no SSL certificate
provided by peer; connection rejected 2017-04-10T11:18:21.560+0530 I
NETWORK [conn64] end connection 127.0.0.1:53901 (0 connections now
open)
I am using c# MongoDB.Driver version 2.3.0
and MongoDB package is of version 3.2.
If you have solution for the above please do reply.

Answer 1

Set the value of allowConnectionsWithoutCertificates to false. Also, you need to combine the certificate and the key file.

Answer 2

In despite of this thread be a little bit old, I faced this exactly same issue today and found a solution at MongoDB.com site (Setup Connection Security code example), so,sharing the solution here for future searchs.
Basically the settings should be created from a connection string and follow the next steps straightforward:
using MongoDB.Bson;
using MongoDB.Driver;
using System;
using System.IO;
using System.Threading.Tasks;
using System.Collections.Generic;
using System.Security.Cryptography.X509Certificates;
class Program
{
static void Main(string[] args)
{
MainAsync().Wait();
}
static async Task MainAsync()
{
var connectionString = "mongodb+srv://<your-server.mongodb.net>/?authSource=%24external&authMechanism=MONGODB-X509&retryWrites=true&w=majority";
var settings = MongoClientSettings.FromConnectionString(connectionString);
settings.ServerApi = new ServerApi(ServerApiVersion.V1);
// You will need to convert your Atlas-provided PEM containing the cert/private keys into a PFX
// use openssl and the following line to create a PFX from your PEM:
// openssl pkcs12 -export -in <x509>.pem -inkey <x509>.pem -out <x509>.pfx
// and provide a password, which should match the second argument you pass to X509Certificate2
var cert = new X509Certificate2("<path_to_pfx>", "<pfx_passphrase>");
settings.SslSettings = new SslSettings
{
ClientCertificates = new List<X509Certificate>(){ cert }
};
var client = new MongoClient(settings);
var database = client.GetDatabase("testDB");
var collection = database.GetCollection<BsonDocument>("testCol");
var docCount = collection.CountDocuments("{}");
Console.WriteLine(docCount);
}
}