Local SMTP Relay Server v2.5 serial key or number

This article is part two of a two-part series on configuring a highly available, on-premises SMTP relay solution. In this part, we walk through setting up the actual SMTP relay services. To learn more about the design and all the preparation work, please read part I.

Setting up anonymous SMTP

Log on to your virtual machine where you installed the SMTP Server feature in part one of this article, open the IIS 6 management console, and navigate to the default SMTP virtual server. Rename it from [SMTP Virtual Server #1] to Anonymous SMTP Relay.

Now right-click on Anonymous SMTP Relay and select “Properties” to configure the virtual server. Below we will walk through the tabs and the different settings.

General

Select the IP address you want the anonymous SMTP relay service to listen on.

Click on the Properties button and configure your logging preference. I roll over logs daily and use local time. I also change the logging directory to the one we prepared earlier.

Click the “Advanced” tab to configure logging properties. I select them all to have everything when needed.

Access

Navigate to the “Access” tab and click on the “Authentication” button.

Check that only Anonymous access is enabled.

Move on to the Connection button. Select “Only the list below” and add the IP addresses you want to allow to connect. You must include the real IP addresses of both LoadMaster nodes for health checking and the IP address of the SMTP relay VIP so that they can connect. Do not forget to add the actual IP address of the clients if you use transparency on the LoadMaster as then you will see those as the connecting IP addresses. I added 192.168.2.70/71 and 192.168.2.201 (VIP). You might also want to (temporarily) add the IP address from where you are testing SMTP if that is your workstation. In my case, this is 172.16.100.10.

Click on the Relay button. Select “Only the list below” and add the IP addresses you want to allow to relay. Add the VIP address of the LoadMaster anonymous SMTP relay service so it can connect. Do not forget you must add the actual IP address of the clients if you use transparency on the LoadMaster as then you will see those as the connecting IP addresses. You can see I added the IP of my LoadMaster anonymous SMTP relay virtual service and that of my test workstation.

Messages

Select the “Messages” tab and fill out the email address where you want the NDR sent. You must also change the Badmail directory to the custom path that you set up.

Right now, you might think, great; we have changed the Badmail directory path, but what about the Drop, Pickup, and Queue directory paths? Well, we can change that in the Metabase.xml file or use PowerShell.

To edit the Metabase.xml, we need to check “Enable Direct Metabase Edit” under the properties of the server itself in IIS 6.0.

Then stop the Anonymous SMTP Relay site.

Open the MetaBase file located at C:\Windows\System32\inetsrv\MetaBase.xml with elevated credentials. Search for and update the paths to the “Badmail,” “Drop,” “Pickup,” and “Queue” directories. Save the Metabase.xml file.

Start the Anonymous SMTP Relay site. When done, you can uncheck “Enable Direct Metabase Edit” again.

But PowerShell is the winner here. A lot easier.

Now some things in IIS SMTP are very complicated to do with PowerShell. The Connection Settings are easily automated. Editing the Relay settings, for example, that comes down to a byte array structure with byte mapping/counting for IP addresses, network ranges, and FQDNs. Manipulating that byte array is not documented. So this route requires a lot of reverse engineering via empirical testing. Trust me, I tried. In the end, I resorted to VBScript for that part, Ouch!

Delivery

On the “Delivery” tab, you have three buttons. For outbound security, select Basic Authentication. Use “apikey” for the username. For the password paste the API key you got when you created the API key for SMTP Relay in SendGrid. Remember that this key was only visible during the creation. You should have saved it somewhere in a secure way. Alternatively, you can create a separate one for each use case. Just give them a proper name in SendGrid. You must know what their use case is to keep your SendGrid environment tidy. You do not want it filled with phantom or unknown API keys, you no longer remember the use for, let alone where you used them.

Make sure you select TLS encryption!

Under delivery, outbound connections, change the TCP port to 587.

Under delivery, advanced, you can set the FQDN to what you want to use. I leave it at the servers DNS name for anonymous SMTP relay. You must configure the smart host for SendGrid, which is smtp.sendgrid.net.

Test & verify

When you have done all the above, you should be able to test the anonymous SMTP relay via a script. You’ll need to change the variables to your specific values.

Finally, rinse and repeat for the second server in your load balanced, highly available design.

Setting up authenticated SMTP

Setting up an authenticated SMTP relay is, in many aspects, the same as setting up anonymous SMTP relay. So here we will focus on the differences. Do not forget the rest of the configuration that is the same as for anonymous SMTP, but remember to change values (paths to directories) where applicable.

Username and password

The first difference is that we need to create at least one local user account for basic authentication over TLS. This user requires no special privileges. Just create one with the same name and password on each server for the authenticated SMTP relay service. You do not need to do anything else. In this example, the user is called “MySmtpAuthUser” with “MySmtpAuthPassword” as a password.

You can create multiple accounts for different use cases so that you don’t have to share passwords. Do make sure you create the same combinations of usernames and passwords on both virtual machines.

General – Change the SMTP port for incoming mail to 587 (TLS)

On the “General” tab of the Authenticated SMTP Relay Properties, we click on Advanced and edit the TCP port to be 587, the default port for mail submission.

Access – Use TLS for secure communication and authentication

Navigate to the “Access” tab and click on the “Authentication” button. Uncheck Anonymous access. Check Basic authentication. Also, check Requires TLS encryption and fill out the FQDN for authenticated SMTP Relay. The one you used to register that virtual service on the LoadMaster in DNS.

When you have installed a proper TLS certificate, it shows up under “Secure communication”. You must select Require TLS encryption.

Test your configuration

The rest of the settings are precisely like for anonymous SMTP relay. So you should look there for guidance. When done, test your setup to verify it works.

Don’t forget, do all the above on both virtual machines in your load balanced, highly available design.

Tips from the field

Test your failovers

When you have configured both servers completely, test failover scenarios. Stop a virtual machine, failover a LoadMaster node. Get a feel for its behavior and adapt your LoadMaster configuration to fit your needs. If something does not work, test your setup and verify it works.

Certificate Validation

For basic authentication with TLS, you need a valid certificate. The certificate can be a commercial one, one from your own PKI, or a self-signed one. Many appliances and software don’t check validity or, perhaps, more accurately put, they ignore certificate validation errors. That means that a self-signed certificate might work in one device or software but not with another.

The solution is to make sure the certificate has a valid certificate chain where ever it is consumed. For Windows, this means we add the required intermediate and root certificates to their respective local machine certificate stores. In the case of a self-signed certificate, we have to add it to the Trusted Root Certification Authorities store for the local machine. The ability to upload and configure intermediate and root certificates will differ with the devices and software.

Let’s look at an example. Our backup software, running on Windows, successfully sends emails to our authenticated SMTP relay service with the FQDN or the IP address. The fact that it cannot validate the certificate chain does not matter. With a PowerShell test script on the same Windows host, however, we do run into an issue with this.

It throws an error: “The remote certificate is invalid according to the validation procedure.”

For this to work, with any certificate (self-signed, own PKI, or commercial), we have a couple of options. The first is to make sure the root certificate and intermediate certificates are available in their respective local machine certificate stores. Once that is done, our PowerShell script runs fine as well. Another approach is to ignore the certificate validation errors. In PowerShell for windows, you can do this via

It also means that you can now use an IP address instead of an FQDN matching what is in the certificate. For testing where you do not have name resolution and cannot use a host file, this comes in handy. Use to

to undo this setting.

Remember that when you use whitelisting, the IP off the host where you run the test script must be in there.

Let’s Encrypt

While “Let’s Encrypt” is popular, automated certificate management can be a challenge. Some devices, appliances, and software do not provide much in terms of automation options, or this is not a readily available skill. So, for this reason, I would not opt for them here. Not unless you have automated certificate renewal entirely worked out for all clients and devices, which potentially goes way beyond the two SMTP relay services on your virtual machines. If you have all that under control, by all means, use “Let’s Encrypt”.

Forgot the SendGrid API key used in IIS SMTP?

Forgot the SMTP password (the API key you got from SendGrid), but had it configured in IIS SMTP already? Grab it with PowerShell!

To send outbound mail, use Web services, or use PDF/report printing in Oracle Application Express, an Instance administrator must enable network services.

If you are running Oracle Application Express with Oracle Database 11g or later, you must enable outbound mail. Starting with Oracle Database 11g Release 1 (11.1), the ability to interact with network services is disabled by default.

By default, the ability to interact with network services is disabled in Oracle Database 11 or later. Therefore, if you are running Oracle Application Express with Oracle Database 11g or later, you must use the package to grant connect privileges to any host for the database user. Failing to grant these privileges results in issues with:

Failing to grant these privileges results in issues with:

• Sending outbound mail in Oracle Application Express.

• Using Web services in Oracle Application Express.

• PDF/report printing.

I’m sure you came here looking for an excellent free SMTP server to send transactional emails to your recipients.

But wait a minute! What’s an SMTP server, and why do you need it?

If this is the first time you hear about it, let me reassure you that it’s nothing too complicated like rocket science (or naming Elon Musk’s son).

So, get ready because after reading this, you’ll know how to choose the best SMTP relay service for your business.

PS: If you already know your SMTP Servers, you can jump right into our amazing list by clicking here!

What is an SMTP Server?

SMTP stands for Simple Mail Transfer Protocol, a TCP/IP protocol used by professional and free SMTP servers to send, receive, and relay messages across the web.

Why do you need an SMTP Server?

Without an SMTP Server, your messages would never reach your recipient’s inbox. To avoid that, you need a digital mail carrier. In this case, let’s call him Bob.

Bob is responsible for delivering your messages to the right person.

But Bob isn’t just a simple mailman. He is also smart, so if he realizes that something is suspicious, he will act as your first line of defense.

To satisfy your visual side, here’s a great depiction of how an SMTP service works:

Now, the only question is whether you need a free SMTP server or a premium SMTP provider to handle your messages.

Let’s find out!

Is a Free SMTP Server the right choice?

Getting amazing tools at no cost sounds like a fantastic idea, especially when they actively contribute to your growth.

While a free SMTP server is useful for someone who’s just starting their business and has no budget, you need to consider the following.

A free plan can benefit someone with a small number of subscribers. However, as your business grows, you’ll soon realize that you need to send more messages.

For example, let’s say you use Google’s free SMTP relay server. The service allows you to send 3,000 emails every month.

While it might sound like a lot, if you have a growing online business, you’ll soon see that investing more in eCommerce email marketing and transactional emails is crucial for your success.

Not to mention that when something’s accessible to anyone, there might be potential spammers among them.

This may also lead to lower deliverability rates and a bad sender reputation.

As you can see, a free SMTP service may be suitable for a new business; however, the more you grow, the more you need to find smarter solutions to cover your needs.

Why choose a Premium SMTP Server?

Do you get goosebumps when you hear words like “paid” and “premium?”

Well, you shouldn’t. Just because something is labeled as premium, it doesn’t mean that you have to spend a fortune on it.

Choosing a premium SMTP service will:

• Allow you to send more transactional emails
• Provide you with better security
• Offer higher deliverability rates for your email campaigns
• Let you track the performance of your emails

Now that you have an idea of the pros and cons of having a free SMTP server and a premium SMTP relay service, let’s explore some of the best solutions.

PS: If you don’t want to go through our list, here’s a cool table summarizing the best two services you can get:

Choosing an SMTP server to simplify email sending shouldn’t be the most difficult task.

So, here are the 11 best premium and free SMTP solutions you can utilize to scale your business.

1. Moosend – Premium SMTP Service- $8/month

SMTP Server Type: Premium

Emails per month: Unlimited

Pricing: $8/month (See all pricing options here)

Moosend is one of the best email marketing automation platforms out there.

When you sign up, the service offers you sophisticated tools and responsive newsletter templates to scale your business.

As it is natural, choosing Moosend’s SMTP is a no-brainer since it’s an ESP (Email Service Provider).

More specifically, the SMTP service is easy-to-use, allowing you to integrate it with your website and start sending transactional emails in a breeze.

To give you an idea, Moosend’s SMTP relay service lets you send order and account confirmations, invoices, and password reset messages.

Not only that, but Moosend’s powerful analytics and tracking system are perfect for monitoring your performance and achieving high email deliverability.

Another big plus of the relay server is that you can protect your IP by taking advantage of the service’s first-class infrastructure and IPs.

While Moosend doesn’t have a free SMTP server option, you can start sending unlimited transactional emails when you sign up for a paid plan.

And to put some ease into your mind, this applies even for the lower-tier plans as well!

To start your email marketing journey, you can sign up here and enjoy the benefits of a premium yet cost-efficient service.

2. Google – Free SMTP Server

SMTP Server Type: Free

Emails per month: 3,000

Google’s SMTP service is one of the most popular free options for those who want to send their first transactional emails.

The company’s global infrastructure minimizes disruptions, favoring simplicity, and easiness when integrating it with various applications.

As a free user, you can configure your SMTP setting through your Gmail or G Suite account and create an App password.

All you need is to select a secure TLS or SSL connection, set your username and password, and choose the right port number.

Apart from simplicity, Google’s SMTP service allows you to send messages from a different email address and receive emails to your Gmail account.

For instance, if you have a business email address, you can add it as a custom domain name and send bulk emails through Gmail.

While Google offers a free SMTP server, you can only send about 100 emails per day or 3,000 per month.

Also, don’t forget that since it’s free, you may encounter potential email deliverability issues caused by other users sending spam emails.

Overall, Google offers an excellent solution for new businesses. Nevertheless, the sending limit won’t be ideal for long-term use.

3. Amazon SES – Free SMTP Server

SMTP Server Type: Free

Emails per month: 62,000

Amazon SES (Simple Email Service) is a cloud-based platform that provides users with a sophisticated SMTP interface.

The SMTP service allows you to integrate Amazon with your email client, app, and so on.

When you do, Amazon SES lets you monitor your activity and reputation, an essential feature for every free SMTP relay server.

Furthermore, the service offers support for some of the most popular authentication methods like SPF, DKIM, and DMARC.

This way, you can be sure that sending emails through Amazon SES’ SMTP service won’t harm your email deliverability.

When it comes to email volume, you can send 62,000 per month but only from an application hosted in Amazon EC2 (Elastic Compute Cloud).

Receiving messages is also free, but only for the first 1,000. After that, Amazon will charge you $0.10 for the next 1k emails you get.

Similarly, if you want to send an email campaign from a different client, Amazon SES will charge you $0.10 for every 1,000 emails.

Overall, Amazon SES is among the top free SMTP options to get your work done. Nevertheless, keep in mind that it works only for Amazon EC2 hosted applications.

4. SMTP2GO – Free SMTP Server

SMTP Server Type: Free

Emails per month: 1,000

SMTP2GO is another free SMTP relay server to send emails, track them, and have an excellent deliverability rate.

The service has an intelligent network with built-in redundancy to handle traffic and make sure your emails get delivered even in case of internet failure.

The powerful tools will assist your email tracking efforts with real-time analytics and spamtrap detection.

Furthermore, when you join the free plan, SMTP2GO offers 1,000 per month and five days of premium email reporting.

While the SMTP service can give you the right tools to ace your emails, the free plan only allows you to deliver ticket support to your recipients.

Besides, the service gives you access to 14 days of toll-free phone support and live chat to learn the ropes and configure the server.

All in all, SMTP2GO is an easy-to-use SMTP solution for new businesses that want to provide their first customers with great support.

5. Postmark – Premium SMTP Service – $10/month

SMTP Server Type: Premium

Emails per month: 10,000

Pricing: $10/month

Postmark’s premium SMTP relay server promises to deliver transactional emails in your customers’ inbox in a breeze.

When you sign up, the software will equip you with sophisticated tools and responsive email templates to create mobile-friendly transactional campaigns.

The email provider also gives you access to fast email delivery and detailed analytics to monitor your open and click-through rates.

When it comes to pricing, Postmark charges you $10 per month, allowing you to send 10,000 emails.

If you exceed the sending limit, though, the email provider will charge you $1,25 per 1,000 emails.

Unfortunately, getting a dedicated IP is an optional add-on that you can get for an additional price per month.

Overall, Postmark is a good SMTP server solution that’s secure, cost-efficient, and easy-to-integrate with your website or applications.

6. SocketLabs – Free SMTP Server

SMTP Server Type: Free

Emails per month: 2,000

SocketLabs is another free SMTP relay server that developers can use to deliver timely bulk emails to their recipients.

The service is perfect for new developers and IT professionals who want high deliverability rates at no cost.

Concerning your monthly email volume, SocketLabs gives you 40,000 free emails for the first month. After that, you’ll get a sending limit of 2,000/month.

Moreover, choosing SocketLabs’ hosted SMTP service will maximize your inbox placement and keep your emails away from spam folders.

The real-time statistics will offer you all the information you need about your delivery status to ensure that everything works as planned.

Furthermore, SocketLabs’ email APIs allow you to integrate your statistics with in-house apps for better access.

Apart from that, the fully-managed cloud SMTP servers and their ability to support DKIM signing, SPF, ISP traffic, and more, make SocketLabs worth a try.

All in all, SocketLabs is among the best free solutions you can get to deliver your transactional emails quickly and efficiently.

7. Mandrill – Premium SMTP Service – $20/month

SMTP Server Type: Premium

Emails per month: 1-500k

Pricing: $20/block per month

Mandrill is a paid Mailchimp add-on for your standard or higher account to deliver personalized transactional emails through an SMTP email server.

While Mandrill doesn’t have a free plan, there’s a transactional email demo you can utilize to send automated emails.

The SMTP relay server also has a vast knowledge base with simple and informative guides. So, you won’t have to worry about configuration.

Nevertheless, keep in mind that the demo has some sending limitations.

More specifically, new users can only send 500 transactional emails to any email address on a verified domain throughout the duration of the demo.

When it comes to the pricing structure, Mandrill is based on a block system where each one is a credit for 25,000 emails.

It’s also good to know that the blocks contain a fixed number of emails, so you can’t buy blocks smaller than 25k.

When you buy a block, the service will give you access to its global infrastructure, detailed analytics, and automatic loop registration.

Overall, Mandrill is an ideal SMTP solution for developers who want to increase their email delivery rate and customize sending.

8. Pepipost – Free SMTP Server

SMTP Server Type: Free

Emails per month: 2,800

Pepipost is another free SMTP server solution to deliver mass-sent emails by configuring its SMTP server.

When it comes to registering, Pepipost gives new users 30,000 free emails for the first 30 days.

After that, you will be able to send only 100 free emails per day (or 2,800 per month) forever.

Pepipost is great for developers and marketers who want to keep track of their users’ opens and clicks.

The smart analytics, along with the service’s AI-powered tools, will help you increase your email deliverability, avoid spam traps, and maintain your sender reputation.

What distinguishes Pepipost’s SMTP service is its 90-day history log that you can revisit to optimize your transactional email strategy.

Not only that, but the relay service gives you the option to integrate its SMTP server with your favorite apps through APIs.

All in all, Pepipost will let you deliver bulk emails and achieve great deliverability using some of the most popular open-source email marketing platforms out there.

9. Mailgun – Premium SMTP Service – $35/month

SMTP Server Type: Premium

Emails per month: 50,000

Pricing: $35/month

Next in line is Mailgun, an SMTP service to send automated transactional emails and track your email deliverability.

While pricing starts at $35 per month for 50k emails, Mailgun also has a pay-as-you-go option that gives you 15,000 emails free emails for three months. Then, you pay only for what you send.

Of course, if you want more than 50k emails but don’t want to switch plans, you can always pay an extra $0.80 for every 1,000 emails.

When it comes to useability, Mailgun’s service is easy-to-integrate with any WordPress site or application, offering a wide selection of features.

Among others, you’ll get access to email address validation tools, inbox placement, and detailed documentation.

As a developer-oriented email delivery service, Mailgun may lack some beginner-friendly features.

So, if you don’t have the necessary knowledge, you might stumble across certain obstacles.

In general, Mailgun’s premium SMTP relay service and advanced tools will ensure that your recipients receive the right message at the right time.

10. Sparkpost – Free SMTP Server

SMTP Server Type: Free

Emails per month: 500

Sparkpost has a place among the free SMTP service solutions you can choose.

However, compared to what we’ve seen so far, the service has the lowest number of free emails you can send.

More specifically, the free plan will give you 15,000 emails for the first month, which then drops to 500/month.

Despite the limited number, the service can benefit businesses who are just getting started with email marketing and want to deliver their first transactional emails to their recipients.

The test account is equipped with predictive analytics, real-time alerts, and engagement insights to monitor your email campaigns and optimize them accordingly.

Apart from analytics, Sparkpost will also give you AMP emails, allowing your recipients to interact with your content dynamically.

This is a great addition that somewhat compensates for the limited number of free emails per month!

Overall, while Sparkpost has stricter sending limits than our previous options, it’s a great starting SMTP option for everyone who wants to send their first transactional emails.

11. Inboxroad – Premium SMTP Service – $69/month

SMTP Server Type: Premium

Emails per month: 100,000

Pricing: $69/month

Last but not least, we have Inboxroad, an SMTP relay server that offers premium services, deliverability, and a dedicated IP.

The server is ideal both for developers and businesses of all sizes that want to deliver marketing or transactional emails.

Some of Inboxroad’s best features include active monitoring and an easy DNS setup that allows you to focus on more pressing matters.

Moreover, another fantastic feature is the service’s ability to connect to existing front-ends or your custom system.

What distinguishes Inboxroad’s SMTP service, though, is its premium SMTP support.

The expert team will contribute to your success, offering advice on how to increase your deliverability rate and scale your business.

Overall, the SMTP relay service is ideal for experienced and inexperienced users who want premium service and actionable advice to nail their deliverability.

Takeaway

Whether you go for a premium or a free SMTP server, you should always keep in mind the needs of a growing business.

While a free solution is always good for your pocket, selecting a more sophisticated relay service will allow you to send more emails and achieve higher deliverability rates.

If you still haven’t decided, why not give our SMTP server a try?

All you need to send unlimited transactional emails is a free account and a subscription to our $10/month plan.

Now, you are ready to scale your business like a pro!

So, what are you waiting for?

Go, go, go!