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SMTP Server (Outgoing Email)

What is an overview of SMTP service?

The ability to provide E-mail services to clients includes two critical functions: SMTP and POP3. Together, they provide the means for clients to send outgoing mail and check for new incoming mail, respectively. SMTP service is the side of e-mail that allows clients to send outgoing e-mail messages to any valid e-mail address. The SMTP server performs two basic but important functions. First, it verifies that anyone attempting to send outgoing e-mail through the SMTP server has the right to do so. Secondly, it sends the outgoing mail and if undeliverable, sends the message back to the sender. Think of the SMTP server in terms of your local post office. Just like snail mail, e-mail is routed in a similar fashion. While it does not cost a client 32 cents to send an e-mail, they must have permission to sent the outgoing e-mail message. The post office requires postage to send the message to the recipient. Real Web Host requires that you have checked one of your POP3 accounts in the last 30 minutes for new e-mail before being allowed to send. Think of checking before sending the same as buying a stamp at the post office. Once this requirement is met the mail is sent to the recipient. However, problems can occur both in the delivery of e-mail and postal mail. Mail is sent to addresses which do not exist, and are therefore returned "address unknown" or "user unknown". Just like the postal service returning your mail with a message "stamped" on it as to why it was not deliverable, so will our SMTP server. When e-mail "bounces", or is returned to you, it is done so because it was undeliverable for one reason or another. Finally, you need to configure your e-mail client so that it knows what SMTP server to use for sending outgoing e-mail messages. In order to send mail through the proper SMTP server, configure your e-mail client to access the SMTP (Outgoing Mail) Server:

What does SMTP stand for?

SMTP stands for Simple Mail Transfer Protocol. This is the generally accepted protocol for outgoing e-mail.

What port does SMTP run on?

Real Web Host's SMTP server runs on port 25. This is important but probably not needed for your e-mail client configuration. You can also use port 26 if your isp blocks port 25.

Can I use my own SMTP server?

Certainly. With your account you have the ability to use your own SMTP server. This allows you to send all of your outgoing e-mail from your domain name rather than through your Internet Service Provider, giving you a more professional look.

What do I use for my SMTP (outgoing) mail server?

Use the following syntax for your SMTP (outgoing) Mail server: If you have domain name pointers, you need to use your original domain name (not any domain pointers). Using domain name pointers rather than your original domain name will not work and you will most likely encounter problems sending outgoing e-mail from your account.

What program does Real Web Host use for SMTP service?

Real Web Host uses a proprietary program for SMTP service and does not disclose this information.

How much e-mail can I send out through the SMTP server at once?

Our SMTP server can handle a very large number (250) of outgoing e-mails per second, enabling all of our clients to have sufficient e-mail access. If you plan to send large amounts of email, you should use the Majordomo mailing list manager, (not available with all packages).

Can I send out unsolicited e-mail?

Absolutely not. Sending out unsolicited e-mail from your Real Web Host virtual server is a direct violation of our Acceptable Uses Policy. Please read our section regarding the Anti-Spam Policy. This includes sending unsolicited e-mail using another SMTP server referencing any websites hosted by Real Web Host. Real Web Host has a "zero-tolerance" for violations of this policy. Failure to abide by this policy by anyone using your mail server will result in termination of your account without eligibility for a refund.

Why can't I send e-mail?

This is a fairly broad problem and could be the result of several factors. Please go through the list below and eliminate each possible problem:

  1. Make sure you have your outgoing SMTP Mail Server set to
  2. Make sure you have a connection to the Internet when trying to send outgoing mail.
  3. Make sure your domain name is using Real Web Host's name servers.
  4. Make sure you have authentication enabled for outgoing email.
  5. Make sure that all recipients have valid e-mail addresses.
  6. Make sure you are using the FULL email address as your username.
If all of the requirements above are met, there should be no other reasons why you cannot possibly send outgoing e-mail through your SMTP server. The most common problem is that a client will forget that they must first check for new e-mail on their account before they can send their outgoing e-mail. Additionally, new clients usually have this problem while their domain name is in the process of being propagated or is in the process of being transferred to Real Web Host, in which case they must simply wait for propagation to take place.

What is mail bombing and how does it effect my e-mail service?

E-mail bombers are malicious programs which intentionally deliver a large number of e-mail messages to your mailbox with the intention of flooding a persons mailbox. Most e-mail bombers are capable of sending out 2-5 e-mail messages per second, delivering many thousands of unwanted e-mail messages to the recipients' mailbox. This would take quite some time to download, and the POP3 server would most likely timeout before completing such a task. To combat these activities, we have setup a mail bomb detector on our SMTP server. This program will automatically detect when any user appears to be the victim of a mail bomb. The program defines a mail bomb as occurring when any client receives 50 e-mail messages from the same sender within a one hour time frame. These messages can be different, it does not matter. If this occurs, please notify us immediately. We will take action to block the sender from continuing with the attack.

Why does the e-mail take a long time to reach the recipient?

Many different factors play into the overall time in transit for e-mail. E-mail sent to you through your Real Web Host account will be delivered and ready immediately because the e-mail is delivered locally on our network rather than a different network across the Internet. The biggest cause for delay in mail delivery is when a certain SMTP server is not reachable. For example, if you were to e-mail [email protected], our SMTP server would first make sure that the domain name "" exists. If not, the mail is sent back to the sender with a "host not found" error. Next, the e-mail is sent to the SMTP server for If the SMTP server is unreachable, it will try again for anywhere from the next 4 hours to 5 days. This is the number one cause for e-mail delivery delays: problems with SMTP servers. Another possible problem could be due to any routing problems between Real Web Host and "". We assure our clients that once you have sent your outgoing mail through your SMTP server, it is automatically sent out for delivery. Beyond this point, there is nothing we can do to speed up the delivery time for e-mail.

Why do e-mail messages I send out to people bounce back to me?

There are many reasons this can happen, but e-mail "bounces" back to the sender usually under 3 conditions:

  1. The domain of the recipient's e-mail address does not exist
  2. The e-mail address of the recipient no longer exists
  3. The SMTP server of the recipient's domain was not reachable for a long period of time.
By "bouncing", your original e-mail message comes back into your Inbox along with a standard error message produced by the SMTP server. This error message should give you a good indication of the problem.

Why is the body of my bounced message truncated?

The SMTP server will automatically truncate the body of all bounced e-mail when the size of the body exceeds 20 Kilobytes.

Why do I get a "recipient not acceptable to your SMTP server" error?

This error usually occurs when the recipient or one or more of the recipients of your e-mail mail message has an invalid e-mail address. For example, if you forget to put an ampersand "@" in the e-mail address, the SMTP server will automatically reject this and will not send the e-mail message. You will need to go through the recipient or recipients of your e-mail message to make sure the syntax ([email protected]) is correct.

What does "the following addresses had permanent fatal errors", "host unknown" mean?

This message is sent back to you, the sender, from the SMTP server. The server is telling you that the "host" you tried to send e-mail to does not exist. The "host" is just the domain name proceeding the "@" in the e-mail address. In the case of [email protected] Web Host, the host would be Real Web Host. If you tried to send a letter via postal mail to a non-existent address, the mail would eventually come back to you with "address unknown" stamped on it by the post office. Similarly, if the host does not exist, then e-mail cannot be delivered, and it is returned to the original sender with a similar message. You will need to verify the spelling of the domain name. Make sure this domain name exists (is registered and in use) otherwise your e-mail will continue to bounce.

What does "the following addresses had permanent fatal errors", "550 Command RCPT User not OK" or "User unknown" mean?

This message is sent back to you, the sender, from the SMTP server. The server is telling you that the "user" you tried to send e-mail to does not exist. The user ([email protected]) may have existed at some point in the past, but is no longer available. As people open and close e-mail addresses, this will happen. Once removed from the system on which they previously had an e-mail account, all e-mail sent to them will bounce back. A simple example would be sending e-mail to [email protected] Web Host. Since we have no user setup under the login "hih3720", the e-mail will bounce back immediately. In order to correct this problem, you will need to contact the recipient and obtain their new e-mail address.

What does it mean by "User Not Local; Relaying Not Permitted"?

You will receive this message when trying to send an e-mail without having configured to authenticate BEFORE sending. You should be able to overcome this error by checking your email client configuration and trying to send the message again.

Categories: 28 | Questions: 909

Categories: 30 | Questions: 183



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