How can I send emails through SSL SMTP with the NET Framework

Question

Is there a way with the  NET Framework to send emails through an SSL SMTP server on port 465   The usual way   System Net Mail SmtpClient  SmtpServer   new System Net Mail SmtpClient  tempurl org     SmtpServer Port   465   SmtpServer EnableSsl   true   SmtpServer Credentials   new System Net NetworkCredential  username    password     SmtpServer Timeout   5000   SmtpServer UseDefaultCredentials   false   MailMessage mail   new MailMessage    mail From   new MailAddress from   mail To Add to   mail CC Add cc   mail Subject   subject  mail Body   content  mail IsBodyHtml   useHtml   SmtpServer Send mail     times out   System Net Verbose  0    1024  SmtpClient   ctor host ssl0 ovh net  port 465  System Net Information  0    1024  Associating SmtpClient 64923656 with SmtpTransport 44624228 System Net Verbose  0    1024  Exiting SmtpClient   ctor    - gt  SmtpClient 64923656 System Net Information  0    1024  Associating MailMessage 17654054 with Message 52727599 System Net Verbose  0    1024  SmtpClient 64923656  Send MailMessage 17654054  System Net Information  0    1024  SmtpClient 64923656  Send DeliveryMethod Network  System Net Information  0    1024  Associating SmtpClient 64923656 with MailMessage 17654054 System Net Information  0    1024  Associating SmtpTransport 44624228 with SmtpConnection 14347911 System Net Information  0    1024  Associating SmtpConnection 14347911 with ServicePoint 51393439 System Net Sockets Verbose  0    1024  Socket 26756241  Socket InterNetwork 2  System Net Sockets Verbose  0    1024  Exiting Socket 26756241  Socket    System Net Sockets Verbose  0    1024  Socket 23264094  Socket InterNetworkV6 23  System Net Sockets Verbose  0    1024  Exiting Socket 23264094  Socket    System Net Sockets Verbose  0    1024  Socket 26756241  Connect 20 465 337754884  System Net Sockets Verbose  0    1024  Exiting Socket 26756241  Connect    System Net Sockets Verbose  0    1024  Socket 23264094  Close   System Net Sockets Verbose  0    1024  Socket 23264094  Dispose   System Net Sockets Verbose  0    1024  Exiting Socket 23264094  Close    System Net Information  0    1024  Associating SmtpConnection 14347911 with SmtpPooledStream 14303791 System Net Sockets Verbose  0    1024  Socket 26756241  Receive   System Net Sockets Verbose  0    2404  Socket 26756241  Dispose   System Net Sockets Error  0    1024  Exception in the Socket 26756241  Receive - A blocking operation was interrupted by a call to WSACancelBlockingCall System Net Sockets Verbose  0    1024  Exiting Socket 26756241  Receive     - gt  0 0 System Net Error  0    1024  Exception in the SmtpClient 64923656  Send - Unable to read data from the transport connection  A blocking operation was interrupted by a call to WSACancelBlockingCall  System Net Error  0    1024     at System Net Sockets NetworkStream Read Byte   buffer  Int32 offset  Int32 size     at System Net DelegatedStream Read Byte   buffer  Int32 offset  Int32 count     at System Net BufferedReadStream Read Byte   buffer  Int32 offset  Int32 count     at System Net Mail SmtpReplyReaderFactory ReadLines SmtpReplyReader caller  Boolean oneLine     at System Net Mail SmtpReplyReaderFactory ReadLine SmtpReplyReader caller     at System Net Mail SmtpConnection GetConnection String host  Int32 port     at System Net Mail SmtpTransport GetConnection String host  Int32 port     at System Net Mail SmtpClient GetConnection      at System Net Mail SmtpClient Send MailMessage message  System Net Verbose  0    1024  Exiting SmtpClient 64923656  Send    System Net Information  0    1024  Associating MailMessage 49584532 with Message 19699911   I googled around and found that System Net Mail supports connections on port 587  default port for Explicit SSL that starts unencrypted then issues a STARTDLS then switches to an Encrypted connection  RFC 2228   but doesn t support Implicit SSL  entire connection is wrapped in an SSL layer

User · Accepted Answer

Here is an example of how to send email through GMail which also uses SSL 465   Minor tweaking of the code below should work   using System Web Mail  using System  public class MailSender       public static bool SendEmail          string pGmailEmail           string pGmailPassword           string pTo           string pSubject          string pBody           System Web Mail MailFormat pFormat          string pAttachmentPath            try               System Web Mail MailMessage myMail   new System Web Mail MailMessage            myMail Fields Add               http   schemas microsoft com cdo configuration smtpserver                              smtp gmail com            myMail Fields Add               http   schemas microsoft com cdo configuration smtpserverport                              465            myMail Fields Add               http   schemas microsoft com cdo configuration sendusing                              2              sendusing  cdoSendUsingPort  value 2  for sending the message using            the network             smtpauthenticate  Specifies the mechanism used when authenticating            to an SMTP            service over the network  Possible values are            - cdoAnonymous  value 0  Do not authenticate            - cdoBasic  value 1  Use basic clear-text authentication             When using this option you have to provide the user name and password            through the sendusername and sendpassword fields            - cdoNTLM  value 2  The current process security context is used to             authenticate with the service          myMail Fields Add           http   schemas microsoft com cdo configuration smtpauthenticate   1              Use 0 for anonymous         myMail Fields Add           http   schemas microsoft com cdo configuration sendusername               pGmailEmail           myMail Fields Add           http   schemas microsoft com cdo configuration sendpassword                pGmailPassword           myMail Fields Add           http   schemas microsoft com cdo configuration smtpusessl                 true            myMail From   pGmailEmail          myMail To   pTo          myMail Subject   pSubject          myMail BodyFormat   pFormat          myMail Body   pBody          if  pAttachmentPath Trim                                MailAttachment MyAttachment                        new MailAttachment pAttachmentPath               myMail Attachments Add MyAttachment               myMail Priority   System Web Mail MailPriority High                     System Web Mail SmtpMail SmtpServer    smtp gmail com 465           System Web Mail SmtpMail Send myMail           return true            catch  Exception ex                throw

User · Answer

You can also connect via port 465  but due to some limitations of the System Net Mail namespace you may have to alter your code  This is because the namespace does not offer the ability to make implicit SSL connections  This is discussed at http   blogs msdn com b webdav 101 archive 2008 06 02 system-net-mail-with-ssl-to-authenticate-against-port-465 aspx   It is possible to make implicit connections without having to use the now obsolete System Web Mail namespace  but you have to access the Microsoft CDO  Collaborative Data Object   I have supplied an example of how to use the CDO in another discussion  GMail SMTP via C   Net errors on all ports    Hope this helps

User · Answer

It works with System Web Mail  which is marked as obsolete    private const string SMTP SERVER           http   schemas microsoft com cdo configuration smtpserver   private const string SMTP SERVER PORT      http   schemas microsoft com cdo configuration smtpserverport   private const string SEND USING            http   schemas microsoft com cdo configuration sendusing   private const string SMTP USE SSL          http   schemas microsoft com cdo configuration smtpusessl   private const string SMTP AUTHENTICATE     http   schemas microsoft com cdo configuration smtpauthenticate   private const string SEND USERNAME         http   schemas microsoft com cdo configuration sendusername   private const string SEND PASSWORD         http   schemas microsoft com cdo configuration sendpassword    System Web Mail MailMessage mail   new System Web Mail MailMessage     mail Fields SMTP SERVER     tempurl org   mail Fields SMTP SERVER PORT    465  mail Fields SEND USING    2  mail Fields SMTP USE SSL    true  mail Fields SMTP AUTHENTICATE    1  mail Fields SEND USERNAME     username   mail Fields SEND PASSWORD     password    System Web Mail SmtpMail Send mail     What is your point of view regarding obsolete namespace usage

User · Answer

Try to check this free an open source alternative  https   www nuget org packages AIM It is free to use and open source and uses the exact same way that System Net Mail is using To send email to implicit ssl ports you can use following code   public static void SendMail             var mailMessage   new MimeMailMessage        mailMessage Subject    test mail       mailMessage Body    hi dude        mailMessage Sender   new MimeMailAddress  you gmail com    your name        mailMessage To Add new MimeMailAddress  yourfriend gmail com    your friendd s name         You can add CC and BCC list using the same way     mailMessage Attachments Add new MimeAttachment  your file address        Mail Sender  Smtp Client       var emailer   new SmtpSocketClient        emailer Host    your mail server address       emailer Port   465      emailer SslType   SslMode Ssl      emailer User    mail sever user name       emailer Password    mail sever password        emailer AuthenticationMode   AuthenticationType Base64         The authentication types depends on your server  it can be plain  base 64 or none     if you do not need user name and password means you are using default credentials     In this case  your authentication type is none                 emailer MailMessage   mailMessage      emailer OnMailSent    new SendCompletedEventHandler OnMailSent       emailer SendMessageAsync          A simple call back function  private void OnMailSent object sender  AsyncCompletedEventArgs asynccompletedeventargs    if  e UserState  null      Console Out WriteLine e UserState ToString     if  e Error    null        MessageBox Show e Error Message   Error   MessageBoxButtons OK  MessageBoxIcon Error     else if   e Cancelled        MessageBox Show  Send successfull     Information   MessageBoxButtons OK  MessageBoxIcon Information

User · Answer

I m late to this party but I ll offer my approach for any passersby that might be interested in an alternative   As noted in previous answers  the System Net Mail SmtpClient class does not support Implicit SSL  It does support Explicit SSL  which requires an insecure connection to the SMTP server over port 25 in order to negotiate the transport level security  TLS   I blogged about my travails with this subtlety here   In short  SMTP over Implict SSL port 465 requires TLS to be negotiated before connecting to the SMTP server  Rather than write a  Net SMTPS implementation I turned to a utility named Stunnel  It s a small service that will let you redirect traffic on a local port to a remote port via SSL      DISCLAIMER  Stunnel uses portions of the OpenSSL library  which recently had a high-profile exploit published in all major tech news media  I believe the latest version uses the patched OpenSSL but please use at your own risk    Once the utility is installed a small addition to the configuration file     Example SSL client mode services  my-smtps  client   yes accept   127 0 0 1 465 connect   mymailserver com 465      instructs the Stunnel service to reroute local requests to port 465 to my mail server on port 465  This happens over TLS  which satisfies the SMTP server on the other end   Using this utility  the following code will successfully transmit over port 465   using System  using System Net  using System Net Mail   namespace RSS SmtpTest       class Program               static void Main  string   args                         try                   using  SmtpClient smtpClient   new SmtpClient   localhost   465           lt -- note the use of localhost                     NetworkCredential creds   new NetworkCredential   username    password                         smtpClient Credentials   creds                      MailMessage msg   new MailMessage   joe schmoe com    jane schmoe com    Test    This is a test                         smtpClient Send  msg                                                catch  Exception ex                     Console WriteLine  ex Message                                      So the advantage here is that you can use Implict SSL and port 465 as the security protocol while still using the send mail methods built into the framework  The disadvantage is that it requires the use of a third party service that may not be useful for anything but this specific function

User · Answer

I know I m joining late to the discussion  but I think this can be useful to others   I wanted to avoid deprecated stuff and after a lot of fiddling I found a simple way to send to servers requiring Implicit SSL  use NuGet and add the MailKit package to the project   I used VS2017 targetting  NET 4 6 2 but it should work on lower  NET versions      Then you ll only need to do something like this   using MailKit Net Smtp  using MimeKit   var client   new SmtpClient    client Connect  server name   465  true       Note  since we don t have an OAuth2 token  disable the XOAUTH2 authentication mechanism  client AuthenticationMechanisms Remove   XOAUTH2     if  needsUserAndPwd           Note  only needed if the SMTP server requires authentication     client Authenticate  user  pwd      var msg   new MimeMessage    msg From Add new MailboxAddress  sender ema il     msg To   Add new MailboxAddress  target ema il     msg Subject    This is a test subject    msg Body   new TextPart  plain         Text    This is a sample message body      client Send msg   client Disconnect true     Of course you can also tweak it to use Explicit SSL or no transport security at all

User · Answer

As stated in a comment at   http   blogs msdn com webdav 101 archive 2008 06 02 system-net-mail-with-ssl-to-authenticate-against-port-465 aspx  with System Net Mail  use port 25 instead of 465      You must set SSL true and Port 25  Server responds to your request from unprotected 25 and then throws connection to protected 465

User · Answer

If any doubt in this code  please ask your questions Here for gmail Port number is 587      code to Send Mail     Add following Lines in your web config file                    lt system net gt                       lt mailSettings gt                         lt smtp gt                             lt network host  smtp gmail com  port  587  userName  xxx gmail com  password  yyy    defaultCredentials  false   gt                         lt  smtp gt                    lt  mailSettings gt                    lt  system net gt     Add below lines in your config file inside appsetting tag  lt appsetting gt  lt  appsetting gt               lt add key  emailFromAddress  value  xxxx gmail com   gt            lt add key  emailToAddress  value  xxxxxxx gmail com   gt             lt add key  EmailSsl  value  true   gt      Namespace Used  using System Net Mail       public static bool SendingMail string subject  string content                  getting the values from config file through c          string fromEmail   ConfigurationSettings AppSettings  emailFromAddress            string mailid   ConfigurationSettings AppSettings  emailToAddress            bool useSSL          if  ConfigurationSettings AppSettings  EmailSsl       true                         useSSL   true                    else                       useSSL   false                       SmtpClient emailClient          MailMessage message          message   new MailMessage            message From   new MailAddress fromEmail           message ReplyTo   new MailAddress fromEmail           if  SetMailAddressCollection message To  mailid                         message Subject   subject              message Body   content              message IsBodyHtml   true              emailClient   new SmtpClient                emailClient EnableSsl   useSSL              emailClient Send message                     return true               if you are sending mail in group      private static bool SetMailAddressCollection MailAddressCollection toAddresses  string    mailId                bool successfulAddressCreation   true          toAddresses Add new MailAddress mailId            return successfulAddressCreation

User · Answer

In VB NET while trying to connect to Rackspace s SSL port on 465 I encountered the same issue  requires implicit SSL   I made use of https   www nuget org packages MailKit  in order to successfully connect    The following is an example of an HTML email message   Imports MailKit Net Smtp Imports MailKit Imports MimeKit  Sub somesub       Dim builder As New BodyBuilder       Dim mail As MimeMessage     mail   New MimeMessage       mail From Add New MailboxAddress     c MailUser       mail To Add New MailboxAddress     c ToUser       mail Subject    Mail Subject      builder HtmlBody     lt html gt  lt body gt Body Text      builder HtmlBody      lt  body gt  lt  html gt         mail Body   builder ToMessageBody          Using client As New SmtpClient         client Connect c MailServer  465  True          client AuthenticationMechanisms Remove  XOAUTH2     Do not use OAUTH2         client Authenticate c MailUser  c MailPassword    Use a username   password to authenticate          client Send mail          client Disconnect True      End Using   End Sub

User · Answer

If it s Implicit SSL  it looks like it can t be done with System Net Mail and isn t supported as of yet   http   blogs msdn com webdav 101 archive 2008 06 02 system-net-mail-with-ssl-to-authenticate-against-port-465 aspx  To check if it s Implicit SSL try this

User · Answer

to expand on Idriss s answer  here s my static method that works like a champ  using System Web Mail   public static void SendEmail String Subject  String sMessage  String EmailAddress  String STMPServer  int SMTPPort  String UserName    quot  quot   String Password   null  Boolean IsSecure   true  Boolean IsHTML   true  String FromAddress    quot no-reply contoso com quot         string SMTP SERVER    quot http   schemas microsoft com cdo configuration smtpserver quot       string SMTP SERVER PORT    quot http   schemas microsoft com cdo configuration smtpserverport quot       string SEND USING    quot http   schemas microsoft com cdo configuration sendusing quot       string SMTP USE SSL    quot http   schemas microsoft com cdo configuration smtpusessl quot       string SMTP AUTHENTICATE    quot http   schemas microsoft com cdo configuration smtpauthenticate quot       string SEND USERNAME    quot http   schemas microsoft com cdo configuration sendusername quot       string SEND PASSWORD    quot http   schemas microsoft com cdo configuration sendpassword quot        MailMessage mail   new MailMessage         mail Fields SMTP SERVER    STMPServer      mail Fields SMTP SERVER PORT    SMTPPort      mail Fields SEND USING    2      mail Fields SMTP USE SSL    IsSecure      if  String IsNullOrEmpty UserName   amp  amp   String IsNullOrEmpty Password                 mail Fields SMTP AUTHENTICATE    1          mail Fields SEND USERNAME    UserName          mail Fields SEND PASSWORD    Password            else               mail Fields SMTP AUTHENTICATE    0            mail From   FromAddress      mail To   EmailAddress      mail Subject   Subject       if  IsHTML                mail BodyFormat   MailFormat Html            else               mail BodyFormat   MailFormat Text            mail Body   sMessage       SmtpMail Send mail

User · Answer

For gmail these settings worked for me  the ServicePointManager SecurityProtocol line was necessary    Because I has setup 2 step verification I needed get a App Password from google app password generator  SmtpClient mailer   new SmtpClient    mailer Host    quot smtp gmail com quot   mailer Port   587  mailer EnableSsl   true  ServicePointManager SecurityProtocol   SecurityProtocolType Tls

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