How to configure SMTP settings in web.config

Question

I'm trying to fix an email issue with an inherited website and don't have access to the code (i.e. just the compiled files). This site needs to be hosted on a new web server having a different SMTP server.

Upon decompiling bits of the code I can see emails are sent using method like below in code snippet and SMTP is set as smtpMail.SmtpServer="localhost" but my new webserver's SMTP server is "relay.tagadab.com" how can we possibly configure this in web.config so that localhost is taken as "relay.tagadab.com"

Imports Microsoft.VisualBasic, System.Web.Mail

Shared Sub SendMail(ByVal ToAdd, ByVal FromAdd, ByVal Message, ByVal Subject)

    Dim msgMail As New MailMessage()

    msgMail.To = ToAdd
    msgMail.From = FromAdd
    msgMail.Subject = Subject
    msgMail.Headers.Add("X-Mailer", "ASP.NET")

    msgMail.BodyFormat = MailFormat.Text
    msgMail.Body = Message
    'SmtpMail.SmtpServer = "mail.the-radiator.com"
    SmtpMail.SmtpServer = "localhost"
    SmtpMail.Send(msgMail)

End Sub

I added this section in my web.config but that does not make a difference

<system.net>
    <mailSettings>
        <smtp>
            <network host="relay.tagadab.com" port="25" />
        </smtp>
     </mailSettings>
</system.net>

Just [configure IIS](http://stackoverflow.com/questions/239262/can-i-configure-smtp-in-iis-so-it-relays-to-a-remote-smtp-server) so that SMTP localhost fowards mail to relay.tagadab.com. — mr_plum, Oct 07 '13 at 20:42
@nunzabar can you kindly give me an example how can we forward it — rumi, Oct 07 '13 at 21:02

score 84 · Answer 1 · edited Oct 02 '22 at 01:05

By setting the values <mailSettings> section of the in the web.config you can just new up an SmtpClient and the client will use those settings.

https://learn.microsoft.com/en-us/dotnet/api/system.net.mail.smtpclient.-ctor?view=net-6.0#system-net-mail-smtpclient-ctor

Web.Config file:

<configuration>
 <system.net>
        <mailSettings>
            <smtp from="yourmail@gmail.com">
                <network host="smtp.gmail.com" 
                 port="587" 
                 userName="yourmail@gmail.com" 
                 password="yourpassword" 
                 enableSsl="true"/>
            </smtp>
        </mailSettings>
</system.net>
</configuration>

C#:

SmtpClient smtpClient = new SmtpClient();
smtpClient.Send(msgMail);

However, if authentication is needed, I would suggest using a configuration provider that is more secure for usernames and passwords and settings them with a NetworkCredentials object.

C#:

SmtpClient smtpClient = 
    new SmtpClient(_configuration.SmtpHost, _configuration.SmtpPort);
smtpClient.Credentials = 
    new NetworkCredential(_configuration.EmailUsername, _configuration.EmailPassword)
smtpClient.Send(msgMail);

Code sample: SmtpClient smtpClient = new SmtpClient(); smtpClient.Send(msgMail); — Dilhan Jayathilake, Mar 14 '17 at 01:26
@Sanjay kumar does it still work? I am receiving the following error when trying to use gmail with smtp: "The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required.". — dpant, Nov 25 '17 at 12:07

score 8 · Answer 2 · answered Feb 05 '17 at 20:33

I don't have enough rep to answer ClintEastwood, and the accepted answer is correct for the Web.config file. Adding this in for code difference.

When your mailSettings are set on Web.config, you don't need to do anything other than new up your SmtpClient and .Send. It finds the connection itself without needing to be referenced. You would change your C# from this:

SmtpClient smtpClient = new SmtpClient("smtp.sender.you", Convert.ToInt32(587));
System.Net.NetworkCredential credentials = new System.Net.NetworkCredential("username", "password");
smtpClient.Credentials = credentials;
smtpClient.Send(msgMail);

To this:

SmtpClient smtpClient = new SmtpClient();
smtpClient.Send(msgMail);

Thank you for the explanation, I almost didn't use the code from the answer above because I didn't understand how it was going to work in my controller. Much appreciated. — Jamie, Nov 13 '18 at 17:46

score 5 · Answer 3 · answered Oct 07 '13 at 21:18

5

Set IIS to forward your mail to the remote server. The specifics vary greatly depending on the version of IIS. For IIS 7.5:

Open IIS Manager
Connect to your server if needed
Select the server node; you should see an SMTP option on the right in the ASP.NET section
Double-click the SMTP icon.
Select the "Deliver e-mail to SMTP server" option and enter your server name, credentials, etc.

answered Oct 07 '13 at 21:18

mr_plum

2,448
1
18
31

I already tried to add a section in web.config (please see my question )but that does not make a difference. I see exactly the same thing in the IIS when I open SMTP email – rumi Oct 07 '13 at 21:28
Looking a little closer, you have to determine how `SmtpMail` is instantiated. Web.config will only be referenced if you use the [default constructor](http://msdn.microsoft.com/en-us/library/system.net.mail.smtpclient.smtpclient.aspx). – mr_plum Oct 08 '13 at 13:03

score 0 · Answer 4 · answered Feb 13 '23 at 17:41

0

This is the actual code in my web.config file sending YetAnotherForum forum emails and also the same code I use in StarterTrack helpDesk.

answered Feb 13 '23 at 17:41

Michael

112
4

How to configure SMTP settings in web.config

4 Answers4

Linked