What is SMTP?
Writing Emails, via Pixabay
The Simple Mail Transfer Protocol (SMTP) is perhaps best known to users of a certain age as "the sent mail server."
This technology has been around since the early '80s, when guidelines were developed to allow communication servers a quick and consistent method for sending electronic mail.
While more intuitive and secure alternatives are currently in development, for most denizens of the Internet, SMTP is the gold standard for getting one's message into the electronic ether.
The Core of SMTP
At its core, SMTP is simply a set of instructions used by servers (whether your own or those of your Internet Service Provider (ISP)) to determine both how to send mail, and who may send it. It was developed in response to threats of widespread e-mail "spam."
While it remains disturbingly easy to send spam anonymously, most hosts have configured their SMTP servers to provide much greater security than the now-infamous open relay configuration.
This security includes, in part:
- Automatic virus scanning on outgoing messages,
- Filters limiting access to outgoing mail servers to customers only
- Inclusion of a traceable Internet Protocol (IP) address linked to message senders.
SMTP and Open Relays
In order for an SMTP relay to not be considered an open relay, it has to meet some requirements. It must be configured in such a way that it will only accept and forward certain types of messages.
- Messages from local or IP addresses to local or non-local mailboxes, or
- From non-local IP addresses to local mailboxes.
These messages must come from e-mail clients that are authorized and authenticated.
So, an SMTP relay that has been secured properly will not accept e-mails from non-local IP addresses to non-local mailboxes when they are from an unauthorized user.
Your Host's SMTP Servers
Should you choose to use your host's SMTP servers, you'll still most likely receive a custom SMTP server configuration using your hosted domain.
And because your messages are still identified by other systems as originating from the "safe" server of your host, they're less likely to be regarded as suspicious by anti-spam security systems on other servers.
How Does SMTP Work to Send and Deliver E-mails?
The mechanism by which SMTP mail gets sent and forwarded is a little bit complicated, but I'll break it down for you.
When You Click "Send"
When you click "send" on an email, you are uploading the text contents and attachments to the email server that hosts the email service. Again, this e-mail server is called the SMTP server. Perhaps this is provided by your web hosting company or by your ISP.
En Route to its Destination
Then, the e-mail service relays the information to the server of your recipient's e-mail service. This mail server will look for the recipient e-mail address and then deliver the information to the POP3 or IMAP server. This server then delivers the e-mail to the client.
An SMTP server can pass mail to another SMTP server. Of course, you can also send mail to people on the same SMTP server as your e-mail service. This means you can send mail to people using an e-mail on the same domain name.
For example, sending e-mail from one Gmail account to another Gmail account would go through this process.
In this case, the SMTP server transfers your mail to its local outgoing server (POP3 or IMAP).
POP3 servers are incoming mail servers. These servers hold onto our e-mail ID's, consisting of our username and password combination. An SMTP server hands the e-mail to the POP3 server after checking that it holds the valid e-mail address that the e-mail is addressed to.
But, POP3 servers present one problem. Once an e-mail client downloads an e-mail from the POP3 server, it no longer holds a copy of the e-mail. This means people wouldn't be able to check e-mails from more than one PC. But, this also means that POP3 will use less server space.
IMAP, on the other hand, does retain a copy of the e-mail on the server so you can access your e-mails from any device.
This means users are able to connect multiple e-mail clients to their e-mail server. As a result, IMAP is much more convenient and is a preference for most people these days.
IMAP is also preferred because it doesn't download attachments automatically. This saves data when viewing your e-mail from your smartphone and also saves time that your client would spend downloading attachments before allowing you to view your e-mails.
IMAP and POP3 both allow you to view your e-mails offline.
What is SMTP Authentication and How Does It Work?
Letters to Email Inbox, via Pixabay
SMTP authentication is necessary for e-mail clients, like Outlook Express, to identify themselves to a mail server. As we know, mail servers will only allow mail to be sent by authorized and authenticated mail clients.
How Authentication Works
So how are e-mail clients authenticated?
- When you send an e-mail, your mail client identifies itself to the mail server using your account's username and password.
- If these credentials are valid, then your email will be relayed to its destination.
You will have to set up your e-mail client with the information it needs to connect to your e-mail server.
How to Setup an SMTP E-mail Account
Once you have e-mail, from a hosting provider or your ISP, you may want to set up your account with an e-mail client. One client people use for this is Outlook Express. This allows people to access mail from an application on their desktop.
How to Access Email From the Control Panel
You can often access your e-mail messages from the control panel provided with your web hosting. But let's say you want access to your e-mail from the desktop of your computer or from your smartphone.
This set-up involves configuring your SMTP server so that it can deliver your e-mails to the client. To do this, you will likely just have to open the e-mail software you have and enter your SMTP parameters.
SMTP Server Specification
You will need to know your SMTP's server specification name. This will look something like name.example.com and should be easily found from your e-mail provider.
You also need the SMTP port number that is used by your incoming and outgoing mail server.
A port is the communication endpoint of your computer's connection to a network.
- Port 25 - The default SMTP port is port 25. But, some IP's will not allow this because it can be affected by spam and malware traffic.
- Port 587 - Most outgoing SMTP servers support port 587 for encrypted connections.
- Port 465 is usually used when connecting with SSL.
If your mail server supports secure socket layer (SSL) or transport layer security (TLS) encryption, then you may want to enable this. This adds a layer of protection that prevents third parties from being able to read your e-mails.
Why Use SMTP With a Web Hosting Account?
Email as Announcement, via Pixabay
In order to send email, you can use the SMTP server provided by your Internet Service Provider (ISP), or you can use the one provided by your web host. For normal email purposes, either will suffice.
There are a few specific advantages to using your host's SMTP for business purposes:
- Professionalism - Sending from your domain email address adds a professional image to your emails, and will give your customers confidence
- Spam Flags - If the sender's domain matches the source of the email, it's less likely to be flagged as spam
- Mass Emails - If you need to send large quantities of email, your ISP will almost certainly reject your messages, so your host's SMTP server is the better option
- Bandwidth Allocation - You may need extra bandwidth to send emails, which might encroach on the allocation for your website (leading to slow page load speeds) - it's better to be prepared and get a larger amount of resources from your host
- Convenience - You can manage everything related to your website and email in one place
Some hosts prefer you to use your ISP's SMTP server and will set their rate limit low to discourage heavy use. The rate limit is the number of emails that can be sent over a specific period.
Sometimes, you can purchase additional "credits" so that you can send mail to more recipients during that period, but this is a clumsy way round the restriction if you frequently send a lot of emails.
Dedicated SMTP Hosting
In some cases, your host may offer an SMTP service that's not suitable for your needs. For example, the host may limit the size of messages you can send, or use the host to send out large numbers of email marketing messages to a mailing list.
If that's the case, you can opt for separate SMTP hosting that's separate to your web hosting account.
Provisions to Check When Purchasing Hosting
If you decide to buy dedicated SMTP hosting, check the provisions carefully:
- Uptime guarantee - Check the uptime guarantee: similar to web hosting, SMTP hosts should provide 99.9% or higher
- Dedicated support - Ensure there's dedicated support for your SMTP service
- Quantity - Make sure you can send a reasonable quantity of email, and ensure there's room to grow as your email marketing list grows
- Additional Features - Look for additional features like autoresponders and email forwarding
- Contacts - Check the mailing list product to see if there's a limit to the number of people you can add
Your Options for SMTP Hosting
For separate SMTP hosting, there are multiple options to check out.
One of these is Greatmail. The company provides hosting for SMTP and allows for bulk e-mail sending with their support of high-volume sending applications.
Their hosting allows you to bypass the restrictions that you may encounter from ISP or web hosting companies.
But bear in mind, these kinds of plans won't be cheap. They're better-suited to large businesses that send over 50,000 emails per month.
For smaller projects, your best bet is to find a web host that supports the e-mail sending requirements that you have. Most common web host providers will give you everything you need for small business SMTP e-mail.
Many hosting providers will list their e-mail features under each of their plans. You basically need to see that they support SMTP, POP3, and IMAP.
It will also be helpful for you if their e-mail server supports third-party clients. This will be useful because may not want to be confined to your hosting account's control panel to check and manage e-mail messages.
Sales and Emails, via Pixabay
If you're running a business where you communicate with customers, you'll likely also want more than one e-mail address.
Your business will look more professional as a result of this.
And, if you have multiple staff on your team, you can give each one of them their own e-mail for work collaboration. Or give out the support e-mail addresses to members of the support team for example.
Many hosting providers allow individual e-mail accounts to choose their own web clients, so they can customize their e-mail environment however they like.
Designing Your Emails
Some hosting providers also offer drag and drop e-mail design and personal branding features. Many of these include e-mail templates which will make it simple for inexperienced designers to create stunning newsletters or promotional announcements.
You know, like the kinds of e-mails that show up in your inbox from clothing stores and blogs you follow. These e-mails have much higher click-through rates than those that just contain plain and simple written text.
Amazon Simple Email Service (Amazon SES)
Another option is Amazon Simple Email Service (Amazon SES). This comes with Amazon Web Services (AWS) which you can use for free for 12 months. Amazon can give you powerful and scalable e-mail sending and receiving solutions through their platform.
This service is targeted more so at businesses and developers. Amazon helps your e-mails reach high deliverability rates with content filtering technologies and dedicated IP addresses.
The best thing about Amazon's e-mail hosting service is that it is extremely cost-effective. You pay as you go and only for what you use.
In the end, you won't pay much if you aren't sending huge numbers of e-mails. With Amazon SES, you can also send e-mail metrics to Amazon CloudWatch that will further analyze your e-mails' performance.
How Not to Spam
There's one problem with SMTP, and that's the danger of misuse.
Originally, SMTP was an open relay by default. An open relay can be used by anyone on the internet, and this was very useful when email servers passed emails from server to server in a relay configuration, as they did in the 1980s.
Spam and Open Relays
As the web matured, the open relay method left SMTP servers wide open to abuse. A spammer could use an open relay to fire out thousands of emails without trace, causing untold spam problems and distributing viruses far and wide.
Since the mid-1990s, security features have been implemented to curb the use of SMTP unless the user is authenticated. Open relays are actually illegal in the United States, and email providers are required to authenticate the person sending the email.
Web Hosts and Anti-Spam
Many hosts, particularly dedicated SMTP hosts, will bundle some kind of virus scanning and spam protection in to the price.
If you're accused of spamming, and you end up on blacklists, you may be granted respite after around four weeks of a spam-free period.
To ensure your emails actually reach their recipients, use our email deliverability checklist.
Don't forget that many hosts offer webmail along their normal email services. Webmail allows you to access your domain email from a browser, and you can choose from a range of email clients depending on the features you need.
Because the majority of hosts include SMTP as part of their services, most users probably won't require a separate SMTP host unless they want to maintain their own outgoing email server or have concerns about maximum file size and port configuration offered by their ISP's SMTP servers.
Those who send out email "blasts" or a large number of newsletters might also be drawn to a separate SMTP host, as many ISPs block what they regard as suspiciously large quantities of outgoing email.
For example, you may run into problems using Gmail to deliver huge quantities of e-mails. And you don't want to risk valuable marketing e-mails not being properly delivered to your potential customers or blog readers.
As always, it's best to check with your host for specific details on what limits may be in place, and what options and services are available.
- With SMTP servers, you can use your own e-mail addresses on your personal or company domain.
- Using your own e-mail address makes your e-mails more credible to receives
- Using your own e-mail also means yours are less likely to be flagged as spam because your domain matches the source of the e-mail
- SMTP servers allow for high volumes of e-mails to be sent at once which is necessary for e-mail marketing campaigns
- SMTP alone doesn't come with a lot of security. Though, many hosting providers include anti-spam protection and e-mail scanning to prevent viruses from reaching your devices
- SMTP hosting can increase the amount you need to allocate to your technology/hosting budget, since it tends to require a stand-alone tool from what you're using for your website
Our Choices: The Top Three Hosts for SMTP
It can be difficult to compare all your webhosting choices, so I've picked out the best hosts based on their SMTP offerings.
SiteGround Home Page
Our winner for the best e-mail hosting on a budget is SiteGround. They provide a customized hosting solution for managing unlimited e-mail accounts on your domain.
To make your life easy, they've added third-party and their own custom solutions to make sure your e-mail experience is fast, secure, and free of spam.
For example, they'll give you anti-spam solutions like SpamExperts enabled by default. And, easily manage your e-mail from their user-friendly control panel. Their e-mail hosting supports SMTP, POP3, and IMAP.
Bluehost Home Page
With Bluehost, you'll get unlimited e-mail accounts and e-mail storage on all but the cheapest of their shared hosting plans. Like SiteGround, Bluehost also has secure POP3 and IMAP support.
Their e-mail server is compatible with third-party clients like RoundCube so you won't have to enter your control panel every time you want to check your e-mail.
Bluehost also gives you unique user account controls so your team can manage their e-mails the way they want.
Web Hosting Hub
Web Hosting Hub Home Page
Similar in price to both Bluehost and SiteGround, WebHostingHub also provides great e-mail hosting support. Even their cheapest shared hosting comes with unlimited e-mail accounts and storage.
And when you host with them, you'll get free advertising credits for Google AdWords. Though the company doesn't have options for higher-performing VPS plans. These may be needed by businesses that require more power and control. SiteGround, on the other hand, has these options.
Other features in Email
SMTP Frequently Asked Questions
- Does my email client support SMTP?
Yes. All email clients support SMTP.
- What is SMTP?
SMTP stands for simple mail transfer protocol. It is the standard protocol used to send email messages.
- How long has SMTP been used?
The components of SMTP started to form in the 1960s and 1970s. Standards began to develop, especially in the context of the government's ARPANET, the forerunner to today's Internet. SMTP was officially outlined by Jon Postel in RFC 788 in November 1981.
- How does SMTP work?
When you compose and send an email message, your email software opens a connection to an SMTP server. This normally involves logging in using a password. To transmit the email, your email software sends a series of text-based commands, including details about the sender, recipient, and content. The server confirms each command, and once the message has been received successfully, it uses DNS records to find out the IP address where the email should be delivered.
- Will my host allow me to use SMTP?
Yes, assuming your plan includes the ability to create email mailboxes. To prevent spam and abuse, each person that sends emails will need a username and password. You can set those up in your control panel.
- Is SMTP secure?
Not always. But it was never designed to be secure, because it was invented when the internet was very small. Keeping SMTP simple, like its name, meant that it was more reliable.
Email delivery has been adapted to tackle modern challenges like spamming, so most servers now require your email software to log in before sending an email. Many also require that the connection between email client and server be encrypted via SSL or TLS to encrypt the login details, and the email message itself. However, that doesn't ensure that the email will be secured from your computer to the recipient's computer. If you want to ensure that nobody can read your emails in transit, you should use something like PGP encryption.
- What are SMTP ports?
Ports are the entry and exit access points for data on a server. An OS can have tens of thousands of ports. Some are reserved for specific kinds of traffic.
- Which ports does SMTP use?
On SMTP servers, ports 25, 587, and 2525 are standard. Some email servers still use port 465, but this is officially deprecated.
- What is the difference between SMTP and POP3 / IMAP?
SMTP is for sending email. POP3 and IMAP are for receiving email.
- Do I need to use SMTP with email forwarding?
No. When you create an email forwarder, you are essentially creating an alias for incoming email. You will need to send email using a different account. Many people use the email SMTP details provided by their ISP, but you could also use a third party webmail service like Gmail.
- Are there any alternatives to SMTP?
There are some vendor-specific alternatives to SMTP, but these aren't offered with regular web hosting accounts.
- Where do I find the SMTP settings for my hosting company?
Before you sign up for a web hosting account, check that email service is included. Some hosts do not allow you to create email addresses alongside your web hosting files.
Assuming you can create email addresses, you'll need to create mailboxes in your hosting control panel, then ask your host for the necessary server information to connect to them.
- What is an MX record?
MX records are part of the DNS record for your domain. They tell other servers where to send email messages for that domain. You don't usually need to add or change MX records, unless your host or email provider instructs you to do so.
- Can I send my email newsletter using my host's SMTP server?
Be very careful when sending a high volume of email messages at once. This can be flagged as abuse or spamming, particularly if you are advertising a business. It's safer to sign up for a mailing list company, and send all of your marketing messages through them. If you do want to host your own list, you should install a mailing list script that provides options to unsubscribe. This is required by law in many countries.
- Why do I get error 554 when trying to send an email?
This usually happens because your SMTP settings are incorrect. You may have the wrong server, the wrong username or password, or the wrong security settings in your email client.