How Does Email Reach Its Destination?

On an average day, the CITES email systems handle hundreds of thousands of messages. If you've ever wondered how that email actually reaches its destination or worried about what happens to your email if there's a power outage or other disaster, then read on. By the end of the document, you should understand how your email is routed and some of the safeguards to help ensure that it reaches its destination, as well as why you are encouraged to use yourNetID@uiuc.edu as your email address. (glossary: NetID)

 

Your unique NetID determines your email address

There are four mail relay computers, located in machine rooms in DCL and another building, so the service will still work even if some of the mail relay computers are down, or one of the buildings has a power outage or other problem.

Once delivered to the email account's mailbox, the message can be read with a variety of mail programs -- for example, through a Web browser; on a properly configured PC or Mac with Eudora or Microsoft Outlook; or on a Linux or Unix machine with Pine.

If your Electronic Directory email field is set to yourNetID@express.cites.uiuc.edu, then your email will be delivered to the CITES Express Email server. You can then read the email using the web interface or with desktop email programs like Microsoft Outlook and Eudora.

 

You can change your Electronic Directory entry's email field by visiting http://ede.cites.uiuc.edu.

What problems can prevent email delivery?

There are a number of safeguards to ensure reliable routing of email (multiple mail relay computers, computers to queue up email if your email system is down, etc.). In cases where email can't be delivered, the cause is almost always due to a problem with the individual email account or email message, not the overall email system. These situations are considered permanent errors that prevent delivery, and email is "bounced" back to the sender with a note explaining why the email couldn't be delivered. Examples of permanent problems are:

• the sender mistypes the email address.
• the recipient has an email account that has exceeded its quota. (glossary: quota)
• the sender's email message is too large to be delivered.
• the recipient has permanently closed, or deleted, his or her email account.
  

A contributing factor in the increase in misdirected email is the University's conscious attempt to assign NetIDs that are mnemonically similar to users' real names instead of reducing each user to a number. This results in a sort of clustering effect around popular names (e.g., jsmith, j-smith, smith) and makes it much more likely that a simple typo will send a message to the wrong person.

If you are sending a message to someone on campus and are unsure of the recipient's email address, an easy way to check is to use the Electronic Directory (also referred to as ED). For instance, if you wanted to email John Smith about an assignment, simply enter "John Smith" into the Electronic Directory search box and choose the appropriate name from the resulting list. If no matching name is found or if there are too many entries to print, you may have to use wild cards or other directory fields to widen or narrow your search. More information on search criteria can be found on the Electronic Directory page.

When an email message cannot be delivered because of an email server or routing problem, it is called a temporary error. Repeated delivery attempts are usually made for several days before giving up, since these problems are normally addressed very quickly by the system administrator. Examples of temporary errors are:

• the server where the email account resides goes down
• the mail relay computer that routes email to the appropriate email address goes down

Temporary errors that are not fixed within a certain amount of time (usually several days) are treated as permanent. The sender would receive a bounceback message stating that the email message could not be delivered.