Email issues account for around 95% of all the calls we receive for technical support and 99% of the time the problem is not with our email server. So why does sending and receiving email have to be so troubling? Well, it really isn’t once you understand how email works on the Internet.
For the vast majority of people right now, the real e-mail system consists of two different servers running on a server machine.
One is called the SMTP server, where SMTP stands for Simple Mail Transfer Protocol. The SMTP server handles outgoing mail.
The other is either a POP3 server or an IMAP server, both of which handle incoming mail. POP stands for Post Office Protocol, and IMAP stands for Internet Mail Access Protocol.
A typical e-mail server looks like this:
That’s just the mail server part of the equation. For an email message to travel from your computer to its destination, it can travel over many Internet connections and networks. Depending on how much traffic there is on the Internet on a particular day, the message could take as little as 3 seconds or as much as 3 days to reach its intended recipient. And if you are using a PC based email client like Outlook, Thunderbird, etc. you add another “leg” to the trip because you have to send or receive emails from your mail server.
Residential ISP vs. Business ISP – Not all Internet Service Is The Same.
If you are using a business email address (joe@mycompany.com), this is viewed by ISPs as third party email address. Many residential ISPs are blocking what is called "Port 25" which is the port used to send e-mail. They are doing this to cut down on the amount of spam that is sent from their networks.
All e-mail sent via the Internet is routed through the port 25, the channel used for communication between an e-mail client and an e-mail server. Even though port 25 blocking will probably become an industry standard, however, the filter can create problems for e-mail servers and block legitimate e-mail as well as spam.
Port 25 blocking allows ISPs to block spam sent out through their networks, but it tends to punish the innocent that have a need to send through e-mail servers other than those belonging to their ISP. The ISPs that block port 25 require their SMTP server to be used instead of the remote SMTP server or a SMTP server running on your computer. This is why you have no problems sending emails from your office connection, but have to reconfigure your SMTP settings in order to send emails on your home connection.
ISPs that block Port 25
This list contains some of the major ISPs that block port 25 on their servers:
AT&T MindSpring
BellSouth MSN
CableOne NetZero
Charter People PC
Comcast ATTBI Sprynet
Cox Sympatico.ca
EarthLink Verio
Flashnet Verizon
MediaOne
AOL, Earthlink And The Other Usual Suspects.
Sending email to someone who has an AOL or Earthlink email address can be challenging. These service providers tout their anti-virus, anti-spamming and other security features as the main reasons to use their service. The only problem is that you never know what emails actually make it through to someone with one of these overpriced accounts. The folks at AOL restrict the types of email attachments you can send to one of their members, but seem to ignore the junk their members send to the rest of the world.
Both AOL and Earthlink are picky about how you send email to their members as well. If your email account is sent using a different domain name, they typically reject it because it appears to them that you are using a “relay server”. This is a common tactic with spammers. Spammers will route email through various servers in order to conceal its origin. So if your website domain is 5flagsweb.com and you send an email from a fiveflagsweb.com address, it may not make it through to your favorite AOL or Earthlink member even though it is routed through the same email server.
Ghosts In The Machine
What frustrates most people is when your email client (Outlook, Outlook Express, Thunderbird, Eudora, etc.) isn’t working as it should. There are many reasons why you have errors sending and receiving emails. The biggest is that your Internet connection has become slow or all together disrupted. If you can’t resolve an email client issue by closing the program and re-starting it, then it may be necessary to re-boot your computer, the modem, routers and sometimes it is necessary to have your IT professional “flush” your local network’s DNS records. Remember, your email is on a server somewhere on the Internet and your email client on your computer is trying to send to or download from that server. It needs a valid Internet connection in order to complete this task.
The bottom line in trying to figure out where the problem lies is to go to the source. If you are having email issues, check your email on the server before you waste time elsewhere.