Hello,
I am developing an application in Visual Basic .NET 2003. My application requires sending an Email to the user's primary Email address. The message needs to be sent as discreetly as possible. I know how to open up Outlook Express and send the message(my Outlook express doesn't work and I don't like Outlook Express anyway). I have been experimenting with System.Web and SMTP unsuccessfully, as I am using XP Home Edition. I would appreciate any advise on how to send Email as discreetly as possible considering all Microsoft Windows Operating Systems.

These are the exceptions I am getting using System.Web SMTP:

(MAIN EXCEPTION)
System.Web.HttpException: Could not access 'CDO.Message' object. ---

(INNER EXCEPTION)
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Runtime.InteropServices.COMException (0x8004020E): The server rejected the sender address. The server response was: 530 5.7.0 Must issue a STARTTLS command first

   --- End of inner exception stack trace ---
   at System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters)
   at System.RuntimeType.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParameters)
   at System.Type.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args)
   at System.Web.Mail.LateBoundAccessHelper.CallMethod(T ype type, Object obj, String methodName, Object[] args)
   at System.Web.Mail.LateBoundAccessHelper.CallMethod(O bject obj, String methodName, Object[] args)
   --- End of inner exception stack trace ---
   at System.Web.Mail.LateBoundAccessHelper.CallMethod(O bject obj, String methodName, Object[] args)
   at System.Web.Mail.CdoSysHelper.Send(MailMessage message)
   at System.Web.Mail.SmtpMail.Send(MailMessage message)
   at Project_1.Notification.Email() in C:\Documents and Settings\******\My Documents\Visual Studio Projects\Project 1\Notification.vb:line 16
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Runtime.InteropServices.COMException (0x8004020E): The server rejected the sender address. The server response was: 530 5.7.0 Must issue a STARTTLS command first

   --- End of inner exception stack trace ---
   at System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters)
   at System.RuntimeType.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParameters)
   at System.Type.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args)
   at System.Web.Mail.LateBoundAccessHelper.CallMethod(T ype type, Object obj, String methodName, Object[] args)
   at System.Web.Mail.LateBoundAccessHelper.CallMethod(O bject obj, String methodName, Object[] args)

This issue comes down to SMTP server permission. The SMTP classes work quite well if you attempt to hit an SMTP server that will accept your message. The error message that you posted indicates that you are trying to send mail thru a server that doesn't want you to send mail thru it.

For most mail servers you can successfully send a message thru it if you meet one of several conditions:

1) You are sending mail to an address that the server recognizes (i.e. you talk to mail.mydomain.com and tell it you have a message for me@mydomain.com. The server handles the mailbox for me@ and accepts a message for it.)

2) You are sending a message thru an SMTP server to which you have already authenticated. This is how many email programs can send messages. You connect to your mailbox server and authentication with a mailbox (POP) login. The server recognizes traffic from your computer as legitimate because you logged in successfully within some time period.

3) You are sending a message from a computer with a permitted IP address. This could be either a public IP that the server knows about or an internal address (LAN). Most corporate email systems and broadband networks are set up this way. They'll accept mail from a LAN address (or public IP address that is within its realm of control) because it is assumed to be legitimate, but other connections are filtered out based on other criteria.

4) (Not 100% sure on this one). You (you@yourdomain.com) send a message to someone else (me@mydomain.com) thru the mail server that should recognize you as a legitimate address (mail.yourdomain.com). If the server can validate your address as legitimate it will accept the message to me.

These are the conditions I am familiar with. If you don't meet one of these, the server will reject your message because it is regarded as mail relay. Typically mail servers are not set up to accept mail relay because it promotes SPAM. It looks like you are falling victim to condition #4.

How you fix this problem is up to your system configuration.

-Peter

So given the conditions, what I'm looking for is something universal that users can EASILY use. Whether its smtp or something else. My understanding was that Windows came with a smtp server that when using the system.web namespace without defining a server would default to it. And thats it. So... My question would be is there a way either configure the windows smtp server to accept and send these messages or is there an alternate route(having them send an email from their primary Email address to their primary Email address)? The main factor is low key. I need it to be sent "automatically". Also aside from the Email issue I'm curious if the msdn article on sms using the compact framework would work from a windows app?

You can make your application send email automatically. You just need to configure it to talk to an SMTP server that will accept the message as I described above.

(Non version specified) Windows doesn't come with an SMTP server by default. Windows machines with Internet Information Server have a SMTP server (or virtual server). However, I've had bad luck with this. Sometimes a message will get accepted but I'll never see it delivered.

Using the .NET SMTP method, if you don't specify the SMTP server name, I do believe that it will default to "localhost". However, this will only be successful if your localhost has an SMTP server running.

-Peter

What about Winsock? I have been searching and have seen some information on using winsock to send email. I am not very familiar with tcp/ip or winsock but is this an option?

In the end, you still need to talk to an SMTP server that will accept your mail message. Regardless of how you send the mail you will be restricted by limitation.

-Peter

OK. Say I set up one of my old pc's as a server. If I specify that computers ip address as the smtp server would it relay the message?(Given it has an smtp server installed)

I have installed several different smtp servers and I'm still getting the same exceptions just as if i had never installed them. What is the problem why is this not working?

Are you still getting "The server rejected the sender address." errors? This doesn't mean that the server isn't working, it just means that the server doesn't like your addresses. Based the SMTP rules, you might still be missing the configuration that allows messages.

You could configure the SMTP server to accept mail relay (NOT advisable if the server is accessible publicly, but OK if it's only visible on your LAN).

-Peter