在Mono LdapException上运行Exchange

Question

我正在尝试通过Mono (版本2.10.8.1 & 3.0.6)在debian上使用Exchange 2，我正在使用vs2012在windows 8上进行开发。

这个程序在windows上运行得很好，我得到了预期的输出。

但是，在mono上，我一直得到以下输出和异常。

<Trace Tag="AutodiscoverConfiguration" Tid="1" Time="2013-03-07 19:09:05Z">
Starting SCP lookup for domainName='example.com', root path=''
</Trace>
Connect Error

Unhandled Exception: LdapException: (91) Connect Error
System.Net.Sockets.SocketException: No such host is known
  at System.Net.Dns.hostent_to_IPHostEntry (System.String h_name, System.String[]          h_aliases, System.String[] h_addrlist) [0x00000] in <filename unknown>:0
  at System.Net.Dns.GetHostByName (System.String hostName) [0x00000] in <filename unknown>:0
  at System.Net.Dns.GetHostEntry (System.String hostNameOrAddress) [0x00000] in <filename unknown>:0
  at System.Net.Dns.GetHostAddresses (System.String hostNameOrAddress) [0x00000] in <filename unknown>:0
  at System.Net.Sockets.TcpClient.Connect (System.String hostname, Int32 port) [0x00000] in <filename unknown>:0
  at System.Net.Sockets.TcpClient..ctor (System.String hostname, Int32 port) [0x00000] in <filename unknown>:0
  at Novell.Directory.Ldap.Connection.connect (System.String host, Int32 port, Int32 semaphoreId) [0x00000] in <filename unknown>:0
[ERROR] FATAL UNHANDLED EXCEPTION: LdapException: (91) Connect Error
System.Net.Sockets.SocketException: No such host is known
  at System.Net.Dns.hostent_to_IPHostEntry (System.String h_name, System.String[] h_aliases, System.String[] h_addrlist) [0x00000] in <filename unknown>:0
  at System.Net.Dns.GetHostByName (System.String hostName) [0x00000] in <filename unknown>:0
  at System.Net.Dns.GetHostEntry (System.String hostNameOrAddress) [0x00000] in <filename unknown>:0
  at System.Net.Dns.GetHostAddresses (System.String hostNameOrAddress) [0x00000] in <filename unknown>:0
  at System.Net.Sockets.TcpClient.Connect (System.String hostname, Int32 port) [0x00000] in <filename unknown>:0
  at System.Net.Sockets.TcpClient..ctor (System.String hostname, Int32 port) [0x00000] in <filename unknown>:0
  at Novell.Directory.Ldap.Connection.connect (System.String host, Int32 port, Int32 semaphoreId) [0x00000] in <filename unknown>:0

很明显，它试图查找一个它找不到的主机。我的windows和linux系统都使用相同的dns服务器，所以这并不是造成问题的原因。

当windows上的跟踪正常工作时，我阅读了它--跟踪显示，查找失败了几次，自动发现方法尝试了几个不同的urls，直到它击中了一个工作正常的urls-但是，在第一个失败之后，它似乎就会掉下来，这就是它的结束。

我已经尝试谷歌使用新闻在mono上，但我还没有找到谁正在这样做，所以我真的不知道还可以尝试什么。

所使用的代码如下所示--几乎所有这些代码都取自http://msdn.microsoft.com/en-us/library/exchange/dd633709(v=exchg.80).aspx上的代码示例。

class Program
{
    private static int verbose = 10;
    private static string loginEmail = "email@example.com";
    private static string password = "#############";

    static void Main(string[] args)
    {
        try
        {

            ServicePointManager.ServerCertificateValidationCallback = CertificateValidationCallBack;

            ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2010_SP2);

            service.Credentials = new WebCredentials(loginEmail, password);

            if (verbose >= 10)
            {

                service.TraceEnabled = true;
                service.TraceFlags = TraceFlags.All;

            }

            service.AutodiscoverUrl(loginEmail, RedirectionUrlValidationCallback);

            Console.WriteLine("AutoDiscover Completed");

            getContacts(service);

            Console.ReadLine();

        }
        catch (Exception e) {
            Console.WriteLine(e.Message);
            foreach (string key in e.Data.Keys)
            {
                Console.WriteLine(String.Format("{0}: {1}",key, e.Data[key]));
            }
            throw e;
        }

    }

    private static void getContacts(ExchangeService service){


        // Get the number of items in the Contacts folder.
        ContactsFolder contactsfolder = ContactsFolder.Bind(service, WellKnownFolderName.Contacts);

        // Set the number of items to the number of items in the Contacts folder or 1000, whichever is smaller.
        int numItems = contactsfolder.TotalCount < 1000 ? contactsfolder.TotalCount : 1000;

        // Instantiate the item view with the number of items to retrieve from the Contacts folder.
        ItemView view = new ItemView(numItems);

        // To keep the request smaller, request only the display name property.
        //view.PropertySet = new PropertySet(BasePropertySet.IdOnly, ContactSchema.DisplayName);

        // Retrieve the items in the Contacts folder that have the properties that you selected.
        FindItemsResults<Item> contactItems = service.FindItems(WellKnownFolderName.Contacts, view);

        // Display the list of contacts. 
        foreach (Item item in contactItems)
        {
            if (item is Contact)
            {
                Contact contact = item as Contact;

                Console.WriteLine();
                Console.WriteLine(contact.DisplayName);
                if (verbose >= 2)
                {
                    Console.WriteLine("    " + contact.Id);
                }

                try
                {
                    Console.WriteLine("    " + contact.EmailAddresses[EmailAddressKey.EmailAddress1].ToString());
                }
                catch (Exception e) 
                {
                    if (verbose >= 5)
                    {
                        Console.WriteLine("    " + "Email Address 1 Not Available : " + e.Message);
                    }
                }
            }
        }

    }

    #region taken from tutorial

    private static bool CertificateValidationCallBack(
        object sender,
        System.Security.Cryptography.X509Certificates.X509Certificate certificate,
        System.Security.Cryptography.X509Certificates.X509Chain chain,
        System.Net.Security.SslPolicyErrors sslPolicyErrors)
    {
        // If the certificate is a valid, signed certificate, return true.
        if (sslPolicyErrors == System.Net.Security.SslPolicyErrors.None)
        {
            return true;
        }

        // If there are errors in the certificate chain, look at each error to determine the cause.
        if ((sslPolicyErrors & System.Net.Security.SslPolicyErrors.RemoteCertificateChainErrors) != 0)
        {
            if (chain != null && chain.ChainStatus != null)
            {
                foreach (System.Security.Cryptography.X509Certificates.X509ChainStatus status in chain.ChainStatus)
                {
                    if ((certificate.Subject == certificate.Issuer) &&
                       (status.Status == System.Security.Cryptography.X509Certificates.X509ChainStatusFlags.UntrustedRoot))
                    {
                        // Self-signed certificates with an untrusted root are valid. 
                        continue;
                    }
                    else
                    {
                        if (status.Status != System.Security.Cryptography.X509Certificates.X509ChainStatusFlags.NoError)
                        {
                            // If there are any other errors in the certificate chain, the certificate is invalid,
                            // so the method returns false.
                            return false;
                        }
                    }
                }
            }

            // When processing reaches this line, the only errors in the certificate chain are 
            // untrusted root errors for self-signed certificates. These certificates are valid
            // for default Exchange server installations, so return true.
            return true;
        }
        else
        {
            // In all other cases, return false.
            return false;
        }
    }

    private static bool RedirectionUrlValidationCallback(string redirectionUrl)
    {
        // The default for the validation callback is to reject the URL.
        bool result = false;

        Uri redirectionUri = new Uri(redirectionUrl);

        // Validate the contents of the redirection URL. In this simple validation
        // callback, the redirection URL is considered valid if it is using HTTPS
        // to encrypt the authentication credentials. 
        if (redirectionUri.Scheme == "https")
        {
            result = true;
        }
        return result;
    }

    #endregion

}

BeepBeep的回答帮助我解决了这个问题。

在使用BeepBeep的建议之后，我遇到了一个问题，即Mono似乎没有dnsapi.dll (根据异常)。我现在跳过自动发现来解决这个问题。

为了做到这一点，我替换了

service.AutodiscoverUrl(loginEmail, RedirectionUrlValidationCallback);

使用

service.Url = new Uri("https://blah.com/ews/exchange.asmx");

然后，我在证书上出现了一个错误(异常说的是'error with或decryption‘之类的东西)--这足以说明，默认情况下，mono不包括任何根ca证书，这里有更多信息：关于安全的单一常见问题

我选择了更懒惰的方式来获得我想要的证书，使用mozroot工具。然而，这并不像预期的那样工作，而且错误仍然存在。

然后，我使用了上述常见问题中的最近一个来确定问题--它与我正在使用的证书链有关(根被接受，但中间层没有被接受)。然后，我使用FAQ (certmgr)中记录的第三个工具来安装证书。

在那之后，一切都成功了。

Answer 1

使用以下代码解决了相同的问题：

ExchangeService service = new ExchangeService();
service.EnableScpLookup = false;