EsSmtp - ActiveX Control

Eurosource, Gruvbyn 415, S-820 50 LOOS, Sweden
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Updated: 1999-05-05

This control encapsulates the SMTP protocol and compile with MIME version 1.0. This means that it can be used to send binary information as well as mail bodies containing characters like the Swedish characters . You can use this control to send mail over the Internet to a server on a UNIX machine or like. The control can also be used as part of Active Server Pages(ASP) to build web applications that supports Internet Mail.

It automatically handles encoding of message bodies in Quoted-Printable if needed. It also allow you to send attachments (binary or text) with your mail and will automatically encode them in BASE64. There is no restriction on the message and/or attachment size.

New features in version 1.1

  1. EsSmtp can now be used in ASP-applications ( Server side scripting ).
  2. A new property SMTPServer is added that resolves internet names and that can be used with both names and IP-addresses.
  3. A Port property is added which gives the possibility to use non standard ports.
  4. A response event has been added which makes it possible to inspect replies sent from the server.
  5. The control now returns the acctual errorcodes received from the server.

Future version will contain the following extra features?

  1. BINHEX attachments will be handled.
  2. The control will support S/MIME (Secure Mime).


Transfer EsSmtp32.OCX to your \windows\system or \winnt35\system32 directory and register it by executing the command:

RegSvr32 \Windows\System\ESSMTP32.OCX

RegSvr32.exe can be found on the Visual Basic 4.0 CD-ROM and in our dll archive ( If RegSvr32.exe fails, it's probably because you don't have the MFC 4.0 DLL library installed on your system. This is available from many sources on the Internet including our ftp archive as MFCDLLS.ZIP. Regsvr32.exe is also included in this archive. If you want to check if you already got the files in they are

  • mfc42.dll
  • msvcrt40.dll
  • oc30.dll
  • olepro32.dll
  • regsvr32.exe


Cookbook or how to use the EsSmtp Control


Create a EsSmtp object for an ASP application

Use the object ID ESSMTP.EsSmtpCtrl.1 when you create an instance of the EsDesCtrl.

So the code

<object RUNAT="server" PROGID="ESSMTP.EsSmtpCtrl.1" id="EsSmtp"> </object>


set EsSmtp = server.CreateObject("EsSmtp.EsSmtpCtrl.1")

will create the object for you.


Send a text message to a SMTP server

Use code as the following to connect to a SMTP server abd send a simple text message.

EsSmtp1.DestinationAddress = ""
EsSmtp1.Domain = ""
EsSmtp1.MailData = "This is a mailmessage"
EsSmtp1.SMTPServer = ""
EsSmtp1.SourceAddress = "MyHost"
EsSmtp1.SourceMailer = "ESSMTP test-mailer"
EsSmtp1.SourceName = "Kalle Karlsson"
EsSmtp1.Subject = "Test of SMTP mail with national characters "

' Set Hourglass
Screen.MousePointer = 11
If (EsSmtp1.SendMail = 1) Then
    MsgBox "OK"
    MsgBox "Failed " + Str$(EsSmtp1.ErrorNo)
End If

' Normal
Screen.MousePointer = 0


Add attachments to a mail

Dim file As String
' Hourglass
Screen.MousePointer = 11
CommonDialog1.DialogTitle = "Add Attachment"
file = CommonDialog1.filename
EsSmtp1.AddAttachment file, 0
' Normal
Screen.MousePointer = 0








Short Acount

Read only.

Attachment count. Increased by one for every attachment added to the mail.



Short AttachmentType( short index )

Read only.

If there are attachments this property fetches the type of a attachment specified by the zero based index. The number of attachments is defined by the Acount property.



String AttachmentPath( short index )

Read only.

If there are attachments this property fetches the full path to an encoded attachment specified by the zero based index. . The number of attachments is defined by the Acount property.



String AttachmentName( short index )

Read only.

If there are attachments this property fetches the filename of a attachment specified by the zero based index. The number of attachments is defined by the Acount property.



String BCCDestinationAddress

The BCC header field. See the DestinationAddress property.



String CCDestinationAddress

The CC (Carbon Copy) header field. See the DestinationAddress property.



BOOL DeliveryReceipt

Set to True to indicate that a delivery receipt is wanted when mail has bee delivered by the SMTP host.

Note that this is not supported among most mail delivery agents.



String DestinationAddress

This is the email addresses for the receivers of this email. You can enter as many as you like separated by a comma.



String Domain

This is your domain on the form



short ErrorNo

Read only.

Holds the last generated error-code. If you get a False return value form a method you should always check the ErrorNo property to determine the cause of the error. There are two types of error messages. One type is the SMTP reply codes and one is the WinSock error codes. Note that not all SMTP reply codes indicates an error.

SMTP reply codes

  • 211 - System status, or system help reply
  • 214 - Help message [Information on how to use the receiver or the meaning of a particular non-standard command; this reply is useful only to the human user]
  • 220 - <domain> Service ready
  • 221 - <domain> Service closing transmission channel
  • 250 - Requested mail action okay, completed
  • 251 - User not local; will forward to <forward-path>
  • 354 - Start mail input; end with <CRLF>.<CRLF>
  • 421 - <domain> Service not available, closing transmission channel [This may be a reply to any command if the service knows it must shut down]
  • 450 - Requested mail action not taken: mailbox unavailable [E.g., mailbox busy]
  • 451 - Requested action aborted: local error in processing
  • 452 - Requested action not taken: insufficient system storage
  • 500 - Syntax error, command unrecognized [This may include errors such as command line too long]
  • 501 - Syntax error in parameters or arguments
  • 502 - Command not implemented
  • 503 - Bad sequence of commands
  • 504 - Command parameter not implemented
  • 550 - Requested action not taken: mailbox unavailable [E.g., mailbox not found, no access]
  • 551 - User not local; please try <forward-path>
  • 552 - Requested mail action aborted: exceeded storage allocation
  • 553 - Requested action not taken: mailbox name not allowed [E.g., mailbox syntax incorrect]
  • 554 - Transaction failed

WinSock error codes

10013 - WSAEACCES, Permission denied.
An attempt was made to access a socket in a way forbidden by its access permissions. An example is using a broadcast address for sendto without broadcast permission being set using setsockopt(SO_BROADCAST).

10048 - WSAEADDRINUSE, Address already in use.
Only one usage of each socket address (protocol/IP address/port) is normally permitted. This error occurs if an application attempts to bind a socket to an IP address/port that has already been used for an existing socket, or a socket that wasn't closed properly, or one that is still in the process of closing. For server applications that need to bind multiple sockets to the same port number, consider using setsockopt(SO_REUSEADDR). Client applications usually need not call bind at all - connect will choose an unused port automatically.

10049 - WSAEADDRNOTAVAIL, Cannot assign requested address.
The requested address is not valid in its context. Normally results from an attempt to bind to an address that is not valid for the local machine, or connect/sendto an address or port that is not valid for a remote machine (e.g. port 0).

10047 - WSAEAFNOSUPPORT, Address family not supported by protocol family.
An address incompatible with the requested protocol was used. All sockets are created with an associated "address family" (i.e. AF_INET for Internet Protocols) and a generic protocol type (i.e. SOCK_STREAM). This error will be returned if an incorrect protocol is explicitly requested in the socket call, or if an address of the wrong family is used for a socket, e.g. in sendto.

10037 - WSAEALREADY, Operation already in progress.
An operation was attempted on a non-blocking socket that already had an operation in progress - i.e. calling connect a second time on a non-blocking socket that is already connecting, or canceling an asynchronous request (WSAAsyncGetXbyY) that has already been canceled or completed.

10053 - WSAECONNABORTED, Software caused connection abort. 
An established connection was aborted by the software in your host machine, possibly due to a data transmission timeout or protocol error.

10061 - WSAECONNREFUSED, Connection refused.
No connection could be made because the target machine actively refused it. This usually results from trying to connect to a service that is inactive on the foreign host - i.e. one with no server application running.

10054 - WSAECONNRESET, Connection reset by peer.
A existing connection was forcibly closed by the remote host. This normally results if the peer application on the remote host is suddenly stopped, the host is rebooted, or the remote host used a "hard close" (see setsockopt for more information on the SO_LINGER option on the remote socket.)

10039 - WSAEDESTADDRREQ, Destination address required.
A required address was omitted from an operation on a socket. For example, this error will be returned if sendto is called with the remote address of ADDR_ANY.

10014 - WSAEFAULT, Bad address.
The system detected an invalid pointer address in attempting to use a pointer argument of a call. This error occurs if an application passes an invalid pointer value, or if the length of the buffer is too small. For instance, if the length of an argument which is a struct sockaddr is smaller than sizeof(struct sockaddr).

10064 - WSAEHOSTDOWN, Host is down.
A socket operation failed because the destination host was down. A socket operation encountered a dead host. Networking activity on the local host has not been initiated. These conditions are more likely to be indicated by the error WSAETIMEDOUT.

10065 - WSAEHOSTUNREACH, No route to host.
A socket operation was attempted to an unreachable host. See WSAENETUNREACH

10036 - WSAEINPROGRESS, Operation now in progress.
A blocking operation is currently executing. Windows Sockets only allows a single blocking operation to be outstanding per task (or thread), and if any other function call is made (whether or not it references that or any other socket) the function fails with the WSAEINPROGRESS error.

10004 - WSAEINTR, Interrupted function call.
A blocking operation was interrupted by a call to WSACancelBlockingCall.

10022 - WSAEINVAL, Invalid argument.
Some invalid argument was supplied (for example, specifying an invalid level to the setsockopt function). In some instances, it also refers to the current state of the socket - for instance, calling accept on a socket that is not listening.

10056 - WSAEISCONN, Socket is already connected.
A connect request was made on an already connected socket. Some implementations also return this error if sendto is called on a connected SOCK_DGRAM socket (For SOCK_STREAM sockets, the to parameter in sendto is ignored), although other implementations treat this as a legal occurrence.

10024 - WSAEMFILE, Too many open files.
Too many open sockets. Each implementation may have a maximum number of socket handles available, either globally, per process or per thread.

10040 - WSAEMSGSIZE, Message too long.
A message sent on a datagram socket was larger than the internal message buffer or some other network limit, or the buffer used to receive a datagram into was smaller than the datagram itself.

10050 - WSAENETDOWN, Network is down. 
A socket operation encountered a dead network. This could indicate a serious failure of the network system (i.e. the protocol stack that the WinSock DLL runs over), the network interface, or the local network itself.

10052 - WSAENETRESET, Network dropped connection on reset.
The host you were connected to crashed and rebooted. May also be returned by setsockopt if an attempt is made to set SO_KEEPALIVE on a connection that has already failed.

10051 - WSAENETUNREACH, Network is unreachable. 
A socket operation was attempted to an unreachable network. This usually means the local software knows no route to reach the remote host.

10055 - WSAENOBUFS, No buffer space available.
An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full.

10042 - WSAENOPROTOOPT, Bad protocol option.
An unknown, invalid or unsupported option or level was specified in a getsockopt or setsockopt call.

10057 - WSAENOTCONN, Socket is not connected.
A request to send or receive data was disallowed because the socket is not connected and (when sending on a datagram socket using sendto) no address was supplied. Any other type of operation might also return this error - for example, setsockopt setting SO_KEEPALIVE if the connection has been reset.

10038 - WSAENOTSOCK, Socket operation on non-socket.
An operation was attempted on something that is not a socket. Either the socket handle parameter did not reference a valid socket, or for select, a member of an fd_set was not valid.

10045 - WSAEOPNOTSUPP, Operation not supported.
The attempted operation is not supported for the type of object referenced. Usually this occurs when a socket descriptor to a socket that cannot support this operation, for example, trying to accept a connection on a datagram socket.

10046 - WSAEPFNOSUPPORT, Protocol family not supported.
The protocol family has not been configured into the system or no implementation for it exists. Has a slightly different meaning to WSAEAFNOSUPPORT, but is interchangeable in most cases, and all Windows Sockets functions that return one of these specify WSAEAFNOSUPPORT.

10067 - WSAEPROCLIM, Too many processes.
A Windows Sockets implementation may have a limit on the number of applications that may use it simultaneously. WSAStartup may fail with this error if the limit has been reached.

10043 - WSAEPROTONOSUPPORT, Protocol not supported. 
The requested protocol has not been configured into the system, or no implementation for it exists. For example, a socket call requests a SOCK_DGRAM socket, but specifies a stream protocol.

10041 - WSAEPROTOTYPE, Protocol wrong type for socket.
A protocol was specified in the socket function call that does not support the semantics of the socket type requested. For example, the ARPA Internet UDP protocol cannot be specified with a socket type of SOCK_STREAM.

10058 - WSAESHUTDOWN, Cannot send after socket shutdown.
A request to send or receive data was disallowed because the socket had already been shut down in that direction with a previous shutdown call. By calling shutdown a partial close of a socket is requested, which is a signal that sending or receiving or both has been discontinued.

10044 - WSAESOCKTNOSUPPORT, Socket type not supported.
The support for the specified socket type does not exist in this address family. For example, the optional type SOCK_RAW might be selected in a socket call, and the implementation does not support SOCK_RAW sockets at all.

10060 - WSAETIMEDOUT, Connection timed out.
A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

10035 - WSAEWOULDBLOCK, Resource temporarily unavailable.
This error is returned from operations on non-blocking sockets that cannot be completed immediately, for example recv when no data is queued to be read from the socket. It is a non-fatal error, and the operation should be retried later. It is normal for WSAEWOULDBLOCK to be reported as the result from calling connect on a non-blocking SOCK_STREAM socket, since some time must elapse for the connection to be established.

11001 - WSAHOST_NOT_FOUND, Host not found.
No such host is known. The name is not an official hostname or alias, or it cannot be found in the database(s) being queried. This error may also be returned for protocol and service queries, and means the specified name could not be found in the relevant database.

(OS dependent) - WSA_INVALID_HANDLE, Specified event object handle is invalid.
An application attempts to use an event object, but the specified handle is not valid.

(OS dependent) - WSA_INVALID_PARAMETER, One or more parameters are invalid.
An application used a Windows Sockets function which directly maps to a Win32 function. The Win32 function is indicating a problem with one or more parameters.

(OS dependent) - WSAINVALIDPROCTABLE, Invalid procedure table from service provider.
A service provider returned a bogus proc table to WS2_32.DLL. (Usually caused by one or more of the function pointers being NULL.)

(OS dependent) - WSAINVALIDPROVIDER, Invalid service provider version number.
A service provider returned a version number other than 2.0.

(OS dependent) - WSA_IO_PENDING, Overlapped operations will complete later.
The application has initiated an overlapped operation which cannot be completed immediately. A completion indication will be given at a later time when the operation has been completed.

(OS dependent) - WSA_IO_INCOMPLETE, Overlapped I/O event object not in signaled state.
The application has tried to determine the status of an overlapped operation which is not yet completed. Applications that use WSAWaitForMultipleEvents in a polling mode to determine when an overlapped operation has completed will get this error code until the operation is complete.

(OS dependent) - WSA_NOT_ENOUGH_MEMORY, Insufficient memory available.
An application used a Windows Sockets function which directly maps to a Win32 function. The Win32 function is indicating a lack of required memory resources.

10093 - WSANOTINITIALISED, Successful WSAStartup not yet performed.
Either the application hasn’t called WSAStartup or WSAStartup failed. The application may be accessing a socket which the current active task does not own (i.e. trying to share a socket between tasks), or WSACleanup has been called too many times.

11004 - WSANO_DATA, Valid name, no data record of requested type.
The requested name is valid and was found in the database, but it does not have the correct associated data being resolved for. The usual example for this is a hostname -> address translation attempt (using gethostbyname or WSAAsyncGetHostByName) which uses the DNS (Domain Name Server), and an MX record is returned but no A record - indicating the host itself exists, but is not directly reachable.

11003 - WSANO_RECOVERY, This is a non-recoverable error.
This indicates some sort of non-recoverable error occurred during a database lookup. This may be because the database files (e.g. BSD-compatible HOSTS, SERVICES or PROTOCOLS files) could not be found, or a DNS request was returned by the server with a severe error.

(OS dependent) - WSAPROVIDERFAILEDINIT, Unable to initialize a service provider.
Either a service provider's DLL could not be loaded (LoadLibrary failed) or the provider's WSPStartup/NSPStartup function failed.

(OS dependent) - WSASYSCALLFAILURE, System call failure. 
Returned when a system call that should never fail does. For example, if a call to WaitForMultipleObjects fails or one of the registry functions fails trying to manipulate theprotocol/namespace catalogs.

10091 - WSASYSNOTREADY, Network subsystem is unavailable.
This error is returned by WSAStartup if the Windows Sockets implementation cannot function at this time because the underlying system it uses to provide network services is currently unavailable. Users should check:

that the appropriate Windows Sockets DLL file is in the current path,

that they are not trying to use more than one Windows Sockets implementation simultaneously. If there is more than one WINSOCK DLL on your system, be sure the first one in the path is appropriate for the network subsystem currently loaded.

the Windows Sockets implementation documentation to be sure all necessary components are currently installed and configured correctly.

11002 - WSATRY_AGAIN, Non-authoritative host not found.
This is usually a temporary error during hostname resolution and means that the local server did not receive a response from an authoritative server. A retry at some time later may be successful.

10092 - WSAVERNOTSUPPORTED, WINSOCK.DLL version out of range.
The current Windows Sockets implementation does not support the Windows Sockets specification version requested by the application. Check that no old Windows Sockets DLL files are being accessed.

10094 - WSAEDISCON, Graceful shutdown in progress.
Returned by recv, WSARecv to indicate the remote party has initiated a graceful shutdown sequence.

(OS dependent) - WSA_OPERATION_ABORTED, Overlapped operation aborted.
An overlapped operation was canceled due to the closure of the socket, or the execution of the SIO_FLUSH command in WSAIoctl.



BOOL fDontRemove

If this property is set to True attachment data is not removed after a call to the send method.



Short Hcount

Read only.

This read only property gives information on how many extra header lines that has been added.



String HeaderData(short index)

This is the place where you handle extra header data. This header data should be entered on the form

X-extra header: some information

If you set this property and use an index of an existing headerdata item (se the property HCount) this item is replaced with the new data. If you use an index that is larger than the number of extra header rows defined this line is added and the property HCount is increased by one. All data must be US-ASCII otherwise an error is thrown. Also it must not contain any CR (0x0d) or LF(0x0a) characters. You should prefix all strings with "X-".

You can also read the header data. You must then remember to set the zero bases index to a value less than HCount.

You can remove a specific row of header data with the RemoveHeaderData method or all Headerdata with the RemoveAllHeaderData method.

Note that extra header data rows is not automatically removed after a send operation. They are available and will be included in all mails until you remove them.



String MailData

This is one place where an outgoing message can be entered. MailData is limited to a maximum of 32768 characters. If you want to send a message that is greater than this you can leave this property empty and send the message as an attachment.

The message is automatically encoded in Quoted Printable if needed. In this case the character set is defined as ISO-8859-1 otherwise US-ASCII and TEXT/PLAIN is used.



String MailTime

Read only.

This is a copy of the date/time field of the message and is set when mail has been transferred to the SMTP server.



Short Port

The Port property is normaly set to 25 the SMTP server port. By changing this value you have the possibility to use non standard ports.



BOOL ReturnRecipt

Set this property to True if you want to receive a confirmation when your mail is read by its receiver(s).

Note that not all mail clients support this.



String SMTPServer

This property holds either the IP-address of the mailserver or the Internet name (including the domain) for the server. If you enter the name for the server EsSmtp resolves the name to an IP-address. This resolved address is available in SMTPServerIP after it has been resolved. This takes place when a mail is sent.

The accepted form is thus either and

This property replaces the old SMTPServerIP and from now on you should use SMTPServer property  instead of the old SMTPServerIP property except for getting information about a resolved IP-address.



String SMTPServerIP

The IP address of the SMTP server on the form

This property is replaced by SMTPServer which support both Internet names and IP-addresses as it's value.



String SourceAddress

This is the users email address on the form



String SourceMailer

This is the name of your mailer application. This can be 'Your mailer application' or what ever you want. It defaults to nothing.



String SourceName

This is your users name as a real text string. If this property contains non US-ASCII characters it is coded in Quoted Printable with the character set ISO-8859-1 before the message is sent.



String Subject

This is the subject line of your message. If this property contains non US-ASCII characters it is coded in Quoted Printable with the character set ISO-8859-1 before the message is sent.



String Xsubtype

Yet to be defined.



String Xtype

Yet to be defined.





BOOL AddAttachment( string file, short type)

Add an attachment to this mail coding it using base64 if needed or sending it as TEXT/PLAIN if no coding is needed.

The file parameter is the path to the file to attach.

Type is the type of the attachment. If set to 0 the type of the attachment is APPLICATION/OCTET-STREAM and it is encoded in base64. This is only done if the file needs to be encoded, otherwise TEXT/PLAIN is used. If set to another value a specific coding is used.

The coding of the file is done when you add the attachment and status events is fired during the coding process. You can use these events to inform your user about the progress of the encoding.

True is returned if the operation was successful.



short SendMail()

Sends the mail, including any attachments, to the SMTP server. Status Events is fired periodically to give information about how much of the job that has been done. You can use these events to inform your user about the progress of the send operation.



BOOL RemoveAttachment( short index )

With this method a specified attachment can be removed. The zero based index specifies the attachment to remove. The Acount property specifies the number of attachments available.

True is returned if the operation was successful.



BOOL RemoveAllAttachments()

With this method all attachments can be removed. This is usually done automatically when a mail has been sent. If the fDontRemove property is set to True they will however not be removed and this method or RemoveAttachment(i) must be used to remove attachments.

True is returned if the operation was successful.



BOOL RemoveHeaderData( short index )

Removes a header data row specified by the zero based index parameter. The number of specified header data rows is available in the HCount property.

True is returned if the operation was successful.



BOOL RemoveAllHeaderData()

Removes all defined HeaderData rows.

Note that this is not automatically done when mail is sent.

True is returned if the operation was successful.




Status (short progress)

Status gives progress information when certain operations is in progress. This can be useful when you need to inform a user about the progress and what is happening during lengthy operations. The progress is directly expressed is percentage of the task completed. A task is always started with an event where progress=0 and ended with an event where progress = 100.

Sendmail and AddAttachment are methods which trigger this event.



Response( LPCTSTR str )

This event gives response text from the server.


Additional Documentation

Where to get the control?

It is possible that you are reading this documentation without having access to the control itself. If you have Internet access you just need to connect to and fetch a fully working sample of the control. At this location you can also find samples on how to use the control.

We can email the control anywhere in the world if you send us a request to do so. Please state if you want MIME or BINHEX coding. Send request to

If you use the unregistered version of the control a splash screen is displayed from time to time reminding you to register.To get rid of this nag-screen you need to register. Information is available at our site.

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You can get support by sending email to You can also find relevant information on-line at

We also check the newsgroup comp.lang.basic.visual.3rdparty on a regular basis and will try to help on all questions posted there.

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  • Eurosource, Gruvbyn 415A, S-820 50 LOOS, SWEDEN