In many companies, users want to be able to access their company email from home, and mobile users want to be able to retrieve both their company and personal email messages from their laptops. Many companies insist that company laptops be configured for email by the IT department, which doesn’t configure the user’s personal email settings. Then users attempt to configure their personal settings themselves, which occasionally undoes the work performed by the IT department. For home desktop computers, the IT department provides instructions for configuring client software to retrieve company mail, but most of the instructions I’ve seen are confusing to users.
The problem is that the IT department doesn’t know the name of the user’s SMTP server when the user is connected to the Internet at home. The IT pros use the company SMTP server name, but accessing it often requires security settings and passwords, which is an unwelcome surprise when the user tries to use the email software. In fact, sometimes the software doesn’t work at all when the user tries to send mail, because the user’s ISP doesn’t permit the use of any SMTP server other than its own. The solution is to tell users how email software works, explaining the components so that the logic of email settings is easier to grasp. Here are instructions about email service components that you can give your users.
There are three components to the email services you use when you’re at home: Your ISP, POP servers, and SMTP servers.
ISP is the Internet Service Provider. This is the company you signed up with to connect you to the Internet. When you’re on the Internet, either to visit Web sites or collect email, you’re getting there through your ISP’s servers.
A POP server is a Point of Presence Server. This is the incoming-mail server that your ISP runs. It’s the place where mail addressed to you is held until you retrieve it. Your ISP records the location of your POP server all over the Internet, which essentially tells all the servers on the Internet, "If you see mail going to email@example.com, send it along to my POP server which is at aaa.xx.yy.zz" (which is the POP server’s unique IP address on the Internet).
Your company maintains a POP server, too, and it might be a company-run POP server, or it might be a POP server run by a service your company pays to maintain email. Email messages sent to you at your company email address, MyName@Company.com (substitute your company’s domain name for "company"), are stored on that POP server and wait there for you to retrieve them.
An SMTP server is a Simple Mail Transfer Protocol server. This is the outgoing mail server, where outgoing mail is placed for a nanosecond. Mail isn't stored on this server; instead, the SMTP server moves the mail out as fast as it comes in. It sends the mail through the Internet to find the POP server that stores mail for addresses that appear in the recipient section of the email (the names you enter in the To: and cc: fields). Your POP server doesn’t know or care what SMTP server you use, and your SMTP server doesn’t know or care what POP server you use. If you signed up with MYISP and your email address is MyName@myisp.com, both that address's POP server and the SMTP server are run by your ISP, but they’re likely to be separate computers and might possibly exist in separate locations. Even if the SMTP and POP servers run by your ISP have the same server name, the processes used for incoming and outgoing mail differ. Each computer and each process is ignorant of the identity and processes of the other.
When you work with email at home, your SMTP server is the one you connect to automatically through your ISP. When you signed up with your ISP, you were given the name of its mail servers, both SMTP and POP. To collect personal mail, you have a mail account that’s configured to get mail from the ISP’s POP server, and you send personal mail through the ISP’s SMTP server.
To collect your company email from home, set up a mail account using your company email address, and specify the company’s POP server name as the POP server (your company IT department will tell you the server’s name). Because you’re working from home, connected to your ISP, specify the SMTP server your ISP uses (the same server you used when you set up your personal mail account). When you’re at home, your outgoing mail goes to the same SMTP server no matter which POP server you’re accessing to collect email.