Relay server overview
A relay server is a server that is mainly used for a function called “mail relay”. In particular, this technology is often used in businesses that have many opportunities to send large volumes of e-mails, such as e-mail newsletters.
Mail relay refers to sending mail through a server that is mainly specialized for sending. Since the protocol (communication procedure/standard) for sending emails is called “SMTP”, it is sometimes called an SMTP relay.
What is “Sending mail through a relay server”?
What does it mean to “send mail through a relay server”?
In a general email, multiple servers work together to send and receive emails. Among them, the type that is responsible for sending mail is called the “SMTP server”.
When a sender sends an e-mail, it first works on its own SMTP server, and from there the e-mail is sent to the other party.
Businesses sometimes send a large number of emails at once, such as email newsletters and autoresponders.
However, most of the mail servers provided mainly by providers have upper limits for sending large amounts of mail.
This is also to prevent spam mail and prevent server load, but business mail, which is often sent in large volumes, tends to exceed the set limit.
Therefore, instead of the mail server that was originally used, a “relay server (SMTP server)” specialized for sending large amounts of mail is used to send mail to the other party.
In this way, the relay server relays and sends the mail.
Benefits of using a relay server
From here, I will introduce the benefits of using a relay server.
cost improvement
If you use a normal server to send a large amount of emails, it may take a long time to send the emails and sometimes the emails may not even arrive.
Also, sending such a large amount of mail puts a load on the server, which may affect the normal sending and receiving of mail.
Even if you strengthen your own mail server, server reinforcement costs time and money, and the more you expand your business, the more you have to strengthen the server.
Since the e-mail function is used regardless of the time of day, there is also a need for personnel to manage the server on a 24-hour basis.
Of course, it is possible to prepare a relay server for each company or individual, but it will cost a lot to maintain.
When using a relay server in business, it will often be outsourced to a company that provides a relay server as a service.
In this case, it will be easier to keep costs down than by increasing your own mail server, and you will be able to respond flexibly to business expansion.
In addition, by outsourcing a server that specializes in delivery, it becomes easier to use transaction emails that are automatically delivered, such as shipping confirmations.
Improving email deliverability
Occasionally, emails that should have been sent may not reach you.
This is an example of an email that has been judged as spam by the recipient and has been rejected.
One of the criteria for judging as spam is the “reputation of the IP address of the sending mail server”.
The evaluation of this IP address is called “IP reputation”, and if this goes down, it will easily be processed as an email with low reliability.
However, managing IP address reputation requires specialized knowledge and skills, and is costly.
This is difficult for most companies to manage, but using a reputable external relay server can increase the reliability of your emails and improve deliverability.
