[General] Mail Sending Problem

I am seeing a lot of support tickets coming in about users having trouble sending out e-mail. I thought I would make a post that would attempt to highlight some of this.

There are basically four ways to send out e-mail from your e-mail application:

• Use our server as a normal SMTP server, configuring your e-mail application to use mail.yourdomain.com

• Use your ISP’s outgoing mail server. This is the recommended setting.

• Use port 587, the message submission port, on our server to send out e-mail.

• Use secure SMTP on our server to send out e-mail.

These are the different ways you can send out e-mail using an e-mail application (Outlook, Thunderbird, etc) with your hosting account.

Why am I suddenly having trouble sending out mail?
We have seen a lot of tickets with similar concerns. Users who have not had any trouble sending out e-mail suddenly experience problems sending out e-mail. The reason for this, more than likely, is that your Internet Service Provers (ISP), the entity that you get your Internet access from, has likely begun blocking remote SMTP servers.

Blocking remote SMTP servers? What does that mean? SMTP is the protocol that is used to send e-mails between servers. When you send an e-mail to a friend or colleague you send the message to your outgoing mail server as it is defined in your e-mail application that server then uses SMTP to send the message to your friend’s or colleague’s mail server. These messages are sent via SMTP through the standard SMTP port, port 25. By default your e-mail application will likely assume that your outgoing mail server is using port 25. Blocking Remote SMTP servers means that your ISP is not allowing you and their end users to connect to these SMTP servers. They are not allowing you to create connections on port 25. The only host that they will allow connections on port 25 to is their outgoing mail server.

Known Internet Service Providers that block remote SMTP

• AT&T Internet Services

• Verizon Internet Services

• Charter Internet Services

• Cox Internet Services

• Earthlink

• Comcast Internet Services

If your Internet is provided by one of these service providers and you are having trouble sending out mail, then your ISP may be blocking remote SMTP servers. Note: This is not a complete list, this is just a list of some ISPs that are known to block remote SMTP servers. If your ISP is not listed here, that does not mean it is not blocking remote SMTP access.

Why do ISPs do this? Spam control more than anything. By blocking remote SMTP servers your ISP is protecting its name and integrity throughout the rest of the Internet as it tries to insure that they stay spam free. Let’s face it, none of us want to be associated with an ISP that knowingly provides service to spammers.

Now that we understand why an ISP might block remote SMTP servers, lets look at what we can do about.

Use our server as a normal SMTP server, configuring your e-mail application to use mail.yourdomain.com
Chances are that if you are reading this post, then this is not an option for you. If your ISP is not blocking remote SMTP servers, then when you set up your e-mail account in your e-mail application then you can specify your outgoing mail server as mail.yourdomain.com where yourdomain.com is your domain name.

Use your ISP’s outgoing mail server.
If your ISP is blocking remote SMTP servers, then they have to provide SMTP service of their own. Some people are concerned that if they use their ISP’s outgoing mail server, then they cannot send out e-mail using @yourdomain.com but this is not true. When you set up the e-mail account in your e-mail application, when it asks for or it configures your outgoing mail server simply enter your ISP’s outgoing mail server hostname. You may need to contact your ISP for this information. Now when you send out e-mail, your message will be from your @yourdomain.com e-mail address, but it will be routed through your ISP’s outgoing mail server.

Use port 587, the message submission port, on our server to send out e-mail.
Our servers do support the message submission port, port 587. To use this you would set your outgoing mail server to mail.yourdomain.com but you will need to change the port to port 587. This may be an advanced setting. In addition to that, you will also need to enable SMTP authentication. Again, this maybe an advanced option. SMTP authentication is a way for the outgoing mail server to authenticate you as someone who has permission to send out mail. To use SMTP authentication you need to specify a username and a password. The username will commonly be the complete e-mail address that you are using and the password will be the corresponding password. The same username and password you would use to check for new mail. If you are checking multiple e-mail accounts, then you can use one SMTP authentication for all of your outgoing messages. The point here is that you want to have each person that sends out mail to use their own unique SMTP authentication username and password. This way, if someone sends out spam, our logs will indicate what SMTP username was used in the authentication process and you can narrow this down to the specific individual.

Use secure SMTP on our server to send out e-mail.
Secure SMTP is a way to securely send out e-mail. Secure SMTP uses SSL in a public/private key combination pair to encrypt your e-mail as it passes from your computer to the mail server. Secure SMTP on our servers runs on port 465, but your e-mail application has to support Secure SMTP. This is because there is some additional negotiations that go on behind the scenes in setting up the secure connection. Most e-mail applications support this, but you have to specifically enable SSL or Secure SMTP for the account. This will be an option when setting up the outgoing mail server, but may be under the advanced options. As with the Message Submission Port, you will have to enable SMTP authentication in order to use Secure SMTP. Read the above paragraph for information on SMTP authentication.

The other issue with Secure SMTP is the hostname to use as your outgoing mail server. You want the hostname to match the hostname on the certificate. If you don’t use the correct hostname, you will get an error about hostname mismatch when sending mail. To figure out what hostname to use follow these steps:

Log into your control panel, visit:
http://www.yourdomain.com/cpanel

Notice that the URL in your address bar will change after you log in. Example:
https://secure.amsnac5.com:2083/frontend/orbit3/index.php

Note the hostname part of this web address:
https://secure.amsnac5.com:2083/frontend/orbit3/index.php

The boldface part is the hostname to use as your outgoing mail server (in this example secure.amsnac5.com your server may vary)

Why is using my ISP’s outgoing mail server recommended?
We recommend using your ISP’s outgoing mail server because your ISP is better equipped to identify any spam-like activities that might be conducted on your account. Your computer may become infected with a virus or a trojan and be used to send out spam. If these messages are sent out through your ISP’s outgoing mail server, your ISP will be able to identify the specific individual that is responsible for this. If you are using our server, we won’t be able to identify the specific individual, just an IP address.

Still, we understand that a lot of you travel and may not be able to always use your ISP’s outgoing mail server. We provide services on the message submission port and SSL port for this purpose. We require SMTP authentication on these ports for added security.

I hope this helps to clear up any questions you might have concerning this. If you have any additional questions, please open a support ticket at:

http://www.amshelp.com

Scott