How does email get from one place to the another

and what can go wrong...

There is a clue to why email does not always work as well as we might like. SMTP stands for Simple Message Transfer Protocol. It worked well in the innocent age when mail servers in government and academic institutions sent sensible messages to the other who operated mail-servers.

When the PC put the technology to read electronic messages on the desk of ordinary folk, the age of the 'simple' system revealed the vulnerability of the emails system upon which the modern world has come to depend. These computers were not clever enough and did not have the right connections to the Internet to be servers.

Because desktop PCs were not mail servers, they needed some way of linking to mail servers and extracting their messages. So a new protocol was developed for the millions of client PCs that we have on our desks to let them exchange messages with servers. POP3, or Post Office Protocol 3, was adopted.

So now messages are passed between the many mail servers around the world. The messages then sit on the server until a client requests that they are delivered. This is why you have to subscribe to an organisation which provides the services of a letterbox for your emails.

The system was not designed for a time when people would abuse it to send spam. Almost every piece of the information in the email header can be faked by those sending spam. To make matters even worse, computers can be taken over by some malware and used to originate messages. As a result, vigilant managers of the mail servers have to detect and shut down individuals or groups of email addresses to block the propagation of spam.

This means that parts of the email system can become unavailable for a period of time that is long enough for the person sending the spam to realise that there is something wrong. Servers can also take themselves off-line to convey the message to the spammers that they are not going to get through.

The interruption can last minutes or hours, so it delays delivery. Nothing is lost. Your outgoing email sits on your computer, while incoming mail waits on one of the servers until it can be delivered. Many systems send you messages telling you there is a problem. These messages can be difficult to interpret but they are useful as you know that your email has not reached its destination.

One way round the problem of your email server going off-line is to sign up for at least two email servers. This means that if one goes down, you just send using another address.

The response of the law-enforcement authorities remains lamentable. There would not be such a pathetic response if people blocked the roads or jammed TV signals. Yet spammers who disrupt communication, block businesses and have increased the costs of computing for everybody are ignored by the authorities.

The problem with the present system is that it works so well. What is needed is some serious attention from the law enforcement agencies to close down those who abuse the system and impose so much cost and inconvenience on the electronic community. If the grey-beards who make the law had access to their favourite bar or shop blocked by crowds, or they had people shouting at them in their office while they tried to work, they might wake up and do something about the crooks behind spam.

The header on your email should show you each server that has handled your email, but sadly that can all be faked, except the identity of the delivering email.

If you want to try and work out what has gone wrong with an email that has bounced back to you, these are the error codes. The first number is generally the most significant.

The five possible values are:

1: The server has accepted the command, but does not yet take action. This is not used at present so you should not see it!

2: The server has completed the task successfully. You only get this if you have requested feedback.

3: The server has understood the request, but requires further information to complete it. So read the message carefully to see what it wants – this is normally a password or some other access permission.

4: The server has encountered a temporary failure. If the command is repeated the message normally gets through. This is not often used by mail servers that just keep trying. But some do give code 4 errors just so that you know they are trying. Others send it back to say they have given up trying so you will need to send it again.

5: The server has encountered an error. These are killers. The email is going nowhere.

If you are still worried, move onto the second ‘error code’ number which gives some more information.

There are 6 values:

0: A syntax error has occurred.

1: Informational reply, for example to a HELP request.

2: Refers to the connection status.

3 and 4 are unspecified.

5: Refers to the status of the mail system as a whole and the mail server in particular.

The final number(s) can provide even more specific information about the mail transfer status. You can check the RFC.com site for details.

Some of the more common SMTP Server Response Codes

Watch out for any of these ‘5’ codes and let your mail server know (but do double-check that you have entered the correct information before you bother them):

Outlook or Outlook Express have some special problems of their own

You get "Socket error: 10061, Error Number: 0x800ccc0e" when you try to send or receive e-mail. This  often means that you need to reset the computer to get the ports working properly.

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