How to send email using gmail.smtp over a proxy server with vb.net

Question

Hello

i am working on a my project, which send email to me using gmail.smtp, it works fine on xp, vista, and + some of windows 7 versions, in few pc's i had tried that, and got a issue.

here is detail of error i got in there, i am using visual studio 2008 & a internet with proxy server,

in my openion its a problem with internet ? maybe ? because when i had used this on my dsl connection it worked.

is there anything to add ? for proxy servers ?

if i compile it & run it via F5 error shows like this

"A first chance exception of type 'System.Net.Mail.SmtpException' occurred in System.dll"

if i run it direct my.exe than error show like this

************** Exception Text **************
System.Net.Mail.SmtpException: Failure sending mail. ---> System.Net.WebException: The remote name could not be resolved: 'smtp.gmail.com'
   at System.Net.ServicePoint.GetConnection(PooledStream PooledStream, Object owner, Boolean async, IPAddress& address, Socket& abortSocket, Socket& abortSocket6, Int32 timeout)
   at System.Net.PooledStream.Activate(Object owningObject, Boolean async, Int32 timeout, GeneralAsyncDelegate asyncCallback)
   at System.Net.PooledStream.Activate(Object owningObject, GeneralAsyncDelegate asyncCallback)
   at System.Net.ConnectionPool.GetConnection(Object owningObject, GeneralAsyncDelegate asyncCallback, Int32 creationTimeout)
   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)
   --- End of inner exception stack trace ---
   at System.Net.Mail.SmtpClient.Send(MailMessage message)

here is my code

i have imported "Imports System.Net.Mail" :D if you ask about it :)

        Dim mail As New MailMessage()
        Dim SmtpServer As New SmtpClient
        Dim Info As String
        Dim Message As String
        SmtpServer.Credentials = New  Net.NetworkCredential(ID.Text, PWD.Text)
        SmtpServer.Port = 587
        SmtpServer.Host = "smtp.gmail.com"
        SmtpServer.EnableSsl = True
        mail.To.Add(To.Text)
        mail.From = New MailAddress("[e-mail]")
        mail.Subject = ("Welcome")
        mail.Body = Message.Text
        SmtpServer.Send(mail)

Thanks in Advance :)

Answer 1

Hello Ashfaq Ahmed Solangi.
it's Simple
Imports System.Net.Mail

Private Sub SendButton_Click(sender As System.Object, e As System.EventArgs) Handles SendButton.Click

message.From = New MailAddress(Me.FormEmailIDTextBox.Text)
message.Body = Me.MessageBodyTextBox.Text
message.Subject = Me.EmailSubjectTextBox.Text
message.To.Add(Me.ToSendEmailIDTextBox.Text)

message.Priority = MailPriority.Normal
'smtp client setting'
smtp.EnableSsl = True
smtp.Port = "587" 'Gmail / Hotmail Port
smtp.Host = "smtp.gmail.com" 'this is gmail, smtp.live.com is hotmail
smtp.Credentials = New Net.NetworkCredential(Me.FormEmailIDTextBox.Text, Me.PassWordFromEmailTextBox.Text)

Try
   smtp.Send(message)
   MsgBox("Send Message Successful")
Catch ex As Exception
   MessageBox.Show("Could not send email...check your settings.")
End Try
End Sub

with regards

Answer 2

Greetings, try the following and see if the same error happens

Imports System.ComponentModel
Imports System.Net.Mail
Imports System.Net

Module GMailCode
    Private mailSent As Boolean = False
    Private Sub SendCompletedCallback(ByVal sender As Object, ByVal e As AsyncCompletedEventArgs)
        Dim token As String = CStr(e.UserState)

        Console.WriteLine("Call back at {0} token [{1}]", Now, token)
        If e.Cancelled Then
            Console.WriteLine("[{0}] [{1}] Send canceled.", Now, token)
        End If
        If e.Error IsNot Nothing Then
            Console.WriteLine("[{0}] [{1}] [{2}]", Now, token, e.Error.ToString())
        Else
            Console.WriteLine("Message sent at {0}", Now)
        End If

        mailSent = True

    End Sub
    ''' <summary>
    ''' 
    ''' </summary>
    ''' <param name="SenderBaseGMailAccount"></param>
    ''' <param name="GMailPassword"></param>
    ''' <param name="Check"></param>
    ''' <param name="SendToEmail"></param>
    ''' <remarks></remarks>
    Sub TestSendGMail( _
        ByVal SenderBaseGMailAccount As String, _
        ByVal GMailPassword As String, _
        ByVal Check As Boolean, ByVal SendToEmail As String)

        Dim Client As New SmtpClient("smtp.googlemail.com", 587)
        Client.DeliveryMethod = SmtpDeliveryMethod.Network
        Client.Credentials = New NetworkCredential(String.Format("{0}@gmail.com", _
                                                   SenderBaseGMailAccount), _
                                                   GMailPassword)

        Client.EnableSsl = True
        Client.Timeout = 20000

        Dim FromAddress As New MailAddress( _
                            String.Format("{0}@gmail.com", SenderBaseGMailAccount), _
                            "Your Name", System.Text.Encoding.UTF8)

        Dim TooAddress As New MailAddress(SendToEmail)

        Dim Message As New MailMessage(FromAddress, TooAddress)
        Message.Body = "This is a test e-mail message do not respond."
        Message.BodyEncoding = System.Text.Encoding.UTF8
        Message.Subject = "test message 1"
        Message.SubjectEncoding = System.Text.Encoding.UTF8

        Dim UserToken As String = "test message1"

        AddHandler Client.SendCompleted, AddressOf SendCompletedCallback
        Client.SendAsync(Message, UserToken)

        ' Do not uncomment
        'message.Dispose()
    End Sub
End Module

Call the above as follows where KSG would be your base email account and the last parm is who the email goes too.

Private Sub Button1_Click( _
    ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button1.Click

    TestSendGMail("KSG", _
                  "My Password", _
                  True, _
                  "[e-mail]")
End Sub

---

KSG

Answer 3

Hello Mind-Reader

it looks great and related to the issue, but for network credential on a proxy internet connection i have just only host name and port, there is not username and password, so how do i use that ?

actually the problem is to link the internet in my application, when i use my app on my 2nd pc where the internet is connected through proxy server this error shows up,  but while on a dsl connection which is directly connected to internet it works fine.

any idea to set a internet source settings in my app to access internet ? while on proxy server

Thanks

Answer 4

Hello Kevininstructo

your code also works but not on a proxy :(

actually the problem is to link the internet in my application, when i use my app on my 2nd pc where the internet is connected through proxy server this error shows up,  but while on a dsl connection which is directly connected to internet it works fine.

any idea to set a internet source settings in my app to access internet ? while on proxy server

Thanks

Answer 5

Hello Kevininstructo

your code also works but not on a proxy :(

actually the problem is to link the internet in my application, when i use my app on my 2nd pc where the internet is connected through proxy server this error shows up,  but while on a dsl connection which is directly connected to internet it works fine.

any idea to set a internet source settings in my app to access internet ? while on proxy server

Thanks

From firsthand experience my company had to setup proxies to allow SMTP messages to be sent, otherwise it would not be possible as they have absolute control. My suggestion for you is to discuss this with those who are responsible for the proxy to allow SMTP message to be sent. If there were, a work around that would breach their security and would not be a wise idea to do so.

---

KSG

Answer 6

Thanks Kevininstructor

i got it now thats the issue i am not able to send :) i did'nt think about it that the proxy server are setuped here to allow just http and https requests inside the isa server, means that i can not access the smtp untill they allow smtp request, am i right ?

Thanks for suggestion one more thing i would like to know, if smtp is not allows so anyother way to send email over server like this ? socks /proxy internet, if yes then what is it ?

or i have a solution for that, can send email using php, thorogh my web server, so i need to send http request to the mail file, if i do this way so how to request my mail.php file over my website from my application ?

Thanks

---

Ashfaq Ahmed Web Programmer + Software Engineer of the world where nothing is impossible :)

Answer 7

The issue is not SMTP but instead how security is setup by whomever is responsible for security of the network and individual computers.

As mentioned before if you figure out something and the security team is on their toes they will find out what you are doing and stop it. Not knowing policies for where this app runs you could get a slap on the wrist or worst case a heavy fine and time in jail.

Bottom line is that how things are setup stopping email message outbound as done a) for security b) network security did not consider an app sending outbound messages thus goes back to my suggestion, talk to those responsible for an exception to the current rules.

---

KSG