B2B Blog

An email client needs to know the IP address of its initial SMTP server and this has to be given as part of its configuration (usually given as a DNS name). This server will deliver outgoing messages on behalf of the user.

Outgoing mail server access restrictions

Server administrators need to impose some control on which clients can use the server. This enables them to deal with abuse, for example spam. Two solutions have been in common use:

• In the past, many systems imposed usage restrictions by the location of the client, only permitting usage by clients whose IP address is one that the server administrators control. Usage from any other client IP address is disallowed.
• Modern SMTP servers typically offer an alternative system that requires authentication of clients by credentials before allowing access.

Restricting access by location

Under this system, an ISP’s SMTP server will not allow access by users who are outside the ISP’s network. More precisely, the server may only allow access to users with an IP address provided by the ISP, which is equivalent to requiring that they are connected to the Internet using that same ISP.

A mobile user may often be on a network other than that of their normal ISP, and will then find that sending email fails because the configured SMTP server choice is no longer accessible.

This system has several variations. For example, an organisation’s SMTP server may only provide service to users on the same network, enforcing this by firewalling to block access by users on the wider Internet. Or the server may perform range checks on the client’s IP address.

These methods were typically used by corporations and institutions such as universities which provided an SMTP server for outbound mail only for use internally within the organization. However, most of these bodies now use client authentication methods, as described below.

Where a user is mobile, and may use different ISPs to connect to the internet, this kind of usage restriction is onerous, and altering the configured outbound email SMTP server address is impractical. It is highly desirable to be able to use email client configuration information that does not need to change.

Client authentication

Modern SMTP servers typically require authentication of clients by credentials before allowing access, rather than restricting access by location as described earlier. This more flexible system is friendly to mobile users and allows them to have a fixed choice of configured outbound SMTP server. SMTP Authentication, often abbreviated SMTP AUTH, is an extension of the SMTP in order to log in using an authentication mechanism.

Open relay

A server that is accessible on the wider Internet and does not enforce these kinds of access restrictions is known as an open relay. This is now generally considered a bad practice worthy of blacklisting.

Ports

Communication between mail servers generally uses the standard TCP port 25 designated for SMTP.

Mail clients however generally don’t use this, instead using specific “submission” ports. Mail services generally accept email submission from clients on one of:

• 587 (Submission), as formalized in RFC 6409 (previously RFC 2476)
• 465 This port was deprecated after RFC 2487, until the issue of RFC 8314.

Port 2525 and others may be used by some individual providers, but have never been officially supported.

Most Internet service providers now block all outgoing port 25 traffic from their customers as an anti-spam measure. For the same reason, businesses will typically configure their firewall to only allow outgoing port 25 traffic from their designated mail servers.

SMTP transport example

A typical example of sending a message via SMTP to two mailboxes (alice and theboss) located in the same mail domain (example.com or localhost.com) is reproduced in the following session exchange. (In this example, the conversation parts are prefixed with S: and C:, for server and client, respectively; these labels are not part of the exchange.)

After the message sender (SMTP client) establishes a reliable communications channel to the message receiver (SMTP server), the session is opened with a greeting by the server, usually containing its fully qualified domain name (FQDN), in this case smtp.example.com. The client initiates its dialog by responding with a HELO command identifying itself in the command’s parameter with its FQDN (or an address literal if none is available).

Email Templates

If you have a targeted lead list and your response rate is less than 10% with personalized emails, your emails could use some work. Earlier this year a B2B company came to me for help with their emails. They offered an incredible service for the SaaS space, but weren’t very successful with their sales emails. Their response rates were below 2%.

In about a month of working together, I created a single sales email template that got them more than 16 new customers. But before I reveal the template, let’s dig into what was wrong with their previous approach.

Why their email were failing:

1. Too long: No one wants to read a mini eBook in an email.
2. Too many ideas: Although the company had an amazing product, they were highlighting too many value props in their emails, which confused readers.
3. Too “me me” Their emails talked way too much about why they were awesome, and listed their company’s features instead of putting it in terms of value for the customer.
4. Too hipster: They wanted to seem young and modern, but overly fancy marketing automation templates made their emails seem impersonal and spammy, even with customization. No one thinks they’re getting a personal email if it’s too pretty.

We’ve gone through the bad, and now it’s time for the good. Here’s the new and improved template they deployed

I have an idea that I can explain in 10 minutes that can get [company] its next 100 best customers.

The results of this email spoke for themselves:

• 57% open rate
• 21% response rate
• Outcome: 16 new customers

1. Exciting subject line

The subject line is your gatekeeper, so 50% of email work should be spent crafting and testing different subject lines. You want to create an exciting but credible (not spammy or sales-y) subject that intrigues recipients.

Make your subject line compelling and informative to pique the recipient’s interest in the body of the email – and research the prospect so the subject line is personalized for them.

2. Enticing offer

Give your prospects a reason to respond, and a simple call-to-action. Who wouldn’t want to “almost triple their monthly run rate?” Mentioning your past success with another client they’ve heard of makes this offer seem more realistic and attainable. Include relevant numbers and statistics to make your offer even more exciting.

3. Personal feel

This sales email has the same basic format and tone of an email you’d send to your mom or best friend. When you’re too formal, you sound stiff and like a salesperson rather than a person-person.

In the example above, the salesperson’s “idea” makes the email less aggressive and aligns with where the recipient is at the beginning of their buyer’s journey. Before you hit the send button, do a final read-through of the email to make sure it has a natural and conversational tone.

4. Social proof

One of your biggest barriers to selling is risk. No one wants to be the first customer and work with a company without credibility or experience, mentioning one of your customers and the results you delivered to them makes you less of a risk.

You can attach client case studies to provide your prospect with a detailed preview of your work. With a compelling example, the prospect will be more inclined to work with you.