Wednesday, April 01, 2020

Setting up an SMTP Relay using SendGrid

I have written several books - some of which have made use of SMTP to send mail. I am currently working on a Storage chapter for my next book. This chapter makes use of File Services Resource Manager (FSRM) to manage file storage. One neat feature of FSRM is its ability to send an email when events occur.

For many, the issue of how to test this has been a challenge, especially if you do not have a happy SMTP server you can use. A neat tool I have used is to use IIS and the SMTP email relay service offered by SendGrid. You can read more about the company here:

Setting up both IIS and the email relay service which SendGrid provides are straightforward to set up. In this blog post, I'll show you how to do this. 

There are 4 simple steps:
1. Setup a SendGrid account Ttheir free service allows you to send 100 emails a day, which should be more than enough for testing.
2. Create a SendGrid API key  The API key is, in essence, your user id and password for the site (so be careful). Make sure you copy/paste the key carefully!
3. Install IIS and configure an email relay using your SendGrid account The GUI is pretty easy to use. There's probably a way using PowerShell, but I've not worked it out yet.
4. Testing your relay And for that, there IS a PowerShell script.

Lets's look at these steps

Setup a SendGrid account

The first step in creating your SMTP relay is to sign up for a (free) account with SendGrid. Like this
1. Navigate to SendGrid.Com (http://Signup.SendGrid.Com) - Use your browser to go to SendGrid's sign up page and fill out your details:

Make sure you create a very strong password. then click ok OK. 

2. This takes you to a page for your personal details Obviously, you should use your real name:

Once you set these details, your account is setup. You should get email from SendGrid asking you to confirm your account. Please do NOT forget to do that.

Create a SendGrid API key

3. Once you have created your SendGrid account, navigate to the Email Integration Guide from SendGrid's Home page:

4. This brings you to the configuration page, where you click to set up your SMTP relay:

5. This takes you to a page where you specify an API Key name and click Generate:

Note that you can use any API Key name from this screen. The API Key name is not used as part of the relay security but is just FYI.

6. After you click on Create Key, SendGrid displays the key and provides some details on how to configure your client:
Please note that in this screenshot, I have obscured MY API key. Since that key is both a user name AND a password for your (or in this case my) account, you need to keep it safe. I recommend at this point cut/past the key form the web browser and save it to a text file. You can not retrieve the plaintext key again so be careful.

Now that you have your account setup and an API key generated, you now need to configure IIS to use this.

Install IIS and configure an Email Relay

The next step is to install IIS and configure the IIS SMTP relay. I assume you are using WIndow Sever 2019. If you need to, you can always download an eval version to use. That gives you 6 months use before you need to activate (or just install and configure a new server). 

7. Install IIS in Windows Server
You use the Add-WindowsFeature command to add IIS to your Windows Server host (e.g. on SRV1.Reskit.Org), like this:

For some reason, this needs a reboot - so go do it!

8. Configure IIS Relay on SRV1
The final step is to set up the SMTP Relay on SRV1. You use the IIS 6 MMC console for this. So start by bringing up the SMTP server tool either from the Start menu (Start/Windows Administrative Tools\Internet Information Server (IIS)  6 Manager or run the application:
C:\Windows\system32\inetsrv\InetMgr6.exe.And select the IIS SMTP Server:

Now bring up the SMTP Virtual Server properties dialog by right-clicking on the SMTP Virtual Server and selecting Properties then click on Access. And select Relay - here you configure which systems can connect. For testing, I set "All except the list below" and leave the list blank, like this:

Click OK.

Next click on the Delivery tab in the SMTP Virtual Server Properties:

From here, click on outbound security and set the user name and password. From this dialog box, select Basic Authentication then enters the user name and password. In this case, the user id is 'apikey' and the password is your API key you set up earlier. Configuring it looks like this:

After clicking OK, click on the Advanced Delivery button to bring up the Advanced Delivery dialog from which you enter the SendGrid server details like this:

And after clicking OK, your relay should be all set up and ready to go. You must need to test it.

Testing your relay

Once you have the relay working on SRV1, you can test it using this little script:

# Test-SendGrid.ps1 - script to test send grid

# Setup key variables
$To         = ''
$Fr         = ''
$Subj       = 'Test Email via SendGrid'
$body       = "testing`ntesting`nTESTING"
$SmtpSrv    = 'SRV1.Reskit.Org'

# And send the email
Send-Mailmessage -To $To -From $Fr -Subj $Subj -Body $body -SmtpServer $SmtpSrv

After sending the mail, you can check in your email client to ensure the mail is sent. If you don't get it, as ever, check your junk mail folder. If that doesn't work do it over and do so very carefully! My personal experience is that API keys can be a challenge. You may need to generate another key.

After sending the mail, you should check in your email client to ensure the mail has been sent and you have received it (it may be in your Junk folder). If you do not get the mail, you need to do some SMTP relay troubleshooting. 


SendGrid provides a simple SMTP EMail Relay Service which you can use to test SMTP enabled applications or services like FSRM.

Thanks to those nice people at Sendgrid for a most useful service!