Learn how SMTP Relay works
Added: (Sat Oct 30 2021)
Pressbox (Press Release) -
E-mail is a critical business tool, but many organizations struggle to manage it effectively. The reasons are many, but one of the biggest is the risk of e-mail being sent over the Internet by unauthorized senders. Email viruses can wreak havoc on an organization’s critical data, while spam can overwhelm users, flooding their inboxes with unwanted messages. And worst of all? An unprotected relay server poses additional security risks that can lead to stolen credentials or malicious software being delivered to the network. No wonder administrators are often hesitant to open up their SMTP servers.
What is an SMTP Server & How Does It Work?
An SMTP or Simple Mail Transfer Protocol server is a messaging device which relays e-mails from one mail server to another mail server. In today’s world, most of these servers are web servers that have been configured to relay e-mails from one mail account to another. For example, if I have a Hotmail account and I want to forward e-mails to my Yahoo! account, the mail is first sent to my Web Server and is relayed by it.
An SMTP server does not accept incoming email for two main reasons. Firstly, to avoid mail storms, where people misconfigure their email settings so all email to them is funneled into the server, then blocked. Secondly, it does not accept email because it isn't used as storage; there are other protocols that are more suited for that purpose. Generally, the only reason an SMTP server accepts incoming email is if it's mail catch-all (basically spam protection) or if it's designed specifically to act as a gateway to the internet (for example, an ISP).
SMTP (Simple Mail Transfer Protocol) is the standard protocol that allows you to send email from your computer to your ISP's or corporate mail server. SMTP is used for mail originating from your computer. Examples include Microsoft Outlook, Mac OS X Mail, iOS Mail, etc.
By using an SMTP relay service, you’re relaying your mail through an intermediary server before sending your messages out into the internet. This gives you (the sender) more control over how your emails are sent, but still doesn’t replace the need for having a high touch email delivery provider for configuration and management of your emails.
What is a Mail Relay?
Mail relay allows a server that is not configured with a mail exchanger (such as one with a statically assigned IP address) to send email. When a server needs to send an email message to a recipient whose domain is hosted by another mail server, the two servers use mail relay to transmit the message. Although you may think of mail relay as a technical problem, it's not uncommon for smaller businesses or those with multiple branches, to have only one mail server for all of their domains. To ensure security, organizations must deploy redundant infrastructure for SMTP so that they can continue sending email uninterrupted in case a single link fails.
Consider this simple example:
Tom’s company may have an Internet-based mail server, or it may use a mail server that is on an internal network, also known as “Intranet.” The incoming MX server on Tom’s company’s Intranet accepts incoming mail, setting up the email on Tom’s computer so he can read it. Since Tom's job is to handle all incoming files into the mailbox of Company B, he needs to be available 24×7 (24 hours a day, 7 days of the week). Mike has requested access to his mailbox 9 pm to 10pm.
An SMTP relay accepts emails from the internet while being a firewall that maintains the integrity of the information. These servers are used for backup email server solutions, email software, mail servers and devices including RBL/DNSBLs, dialup internet connections, and custom applications.
Think we missed something? Have an interesting idea? Contact us at sales@adcrux.io to get in touch!