Port 25 is still known as the standard SMTP port and it’s used mostly for SMTP relay. Port 25 was established all the way back in 1982, which makes it the oldest SMTP port. Join 20,000+ others who get our weekly newsletter with insider WordPress tips! Want to know how we increased our traffic over 1000%? Instead, there are four common SMTP ports:
On the modern web, there’s not a single SMTP port. While “relay” is definitely an important part of SMTP, most people don’t need to configure their own email server. If you’re setting up your email client or WordPress site, you’re mostly concerned with the “submission” part of the process. So after an email is “submitted” to the outgoing mail server, the outgoing mail server “relays” that message to the recipient’s mail server. Relay – the process of relaying the message between two servers.For example, when you send an email in Apple Mail, that message needs to be submitted to the outgoing mail server. Submission – submitting an email message to an outgoing mail server.There are two broad stages in SMTP transmission:
Different Ports for Different Purposesīeyond the implications above, different SMTP ports also have different purposes. However, there are multiple common SMTP ports (more on this next) and not all of them work in all situations.įor example, port 25, the standard SMTP port for moving messages between mail servers, is often blocked by ISPs and cloud providers (including Google Cloud Platform, which is what Kinsta uses).Īs such, if you try to connect to an SMTP server via port 25, you’ll often encounter issues because so many services block port 25. If you want to connect to an SMTP server (like the Gmail SMTP Server), you need to enter both its IP address and its port number. IANA, the organization responsible for global IP address allocation and other tasks, is also responsible for registering port numbers for common Internet services, which includes SMTP. If you want to deliver something to that business, you can’t just address it to the business complex, you also need a way to make sure it gets to the right place inside the business complex.
A port is the number of a specific business in that business complex. Here’s an analogy to make it a little more human-friendly:Īn IP address is the physical street address of a business complex. A port identifies a specific application/service running on that computer, like SMTP.Mail servers are much like website servers in that, while there might be a user-friendly front-facing domain name, the actual communication happens via IP addresses, like 222.501.285.45 (for more on how this happens, check out our introduction to the Domain Name System, or DNS).Ī “port” is another way to help computers ( like two mail servers) communicate with one another: Then, the outgoing mail server needs a way to transfer your email to the recipient’s incoming mail server. Compareįor example, when you send an email, your email client needs a way to upload the email to the outgoing mail server. See how Kinsta stacks up against the competition.
0 kommentar(er)
