by George Spain, CCIT Technical Writer

Like many bad things, it begins with good intention. You’re going on vacation and you want everyone to know why you won’t be answering your e-mail for two weeks. You set up a “rule” to automatically reply to all e-mail you receive. It’s an innocent little option that sniffs incoming messages and fires off a reply to the sender. The sender gets the notice that you will be gone for two weeks.

That’s the ideal, anyway. In practice, it’s different—and more sinister.

Two can play that game

All goes well until your auto-reply is sent to another user who is also enjoying a vacation and has also set up an auto-reply. His reply responds to your reply, which responds to his reply ... well, you get the picture. Ping-Pong replies of this kind can grow into the thousands and bring MUSC’s e-mail system to a standstill.

A variation for more than two players

You’re a member of a department which has its own mailing list. The department head sends out a message to the list, which sends it to you.

While you’re relaxing somewhere, your auto-reply sniffs the message and promptly returns your polite little note to the sender—which is the departmental list—which is everybody in the department —which may be hundreds of people, any of whom may also be on vacation and may have, thoughtfully, set up an auto-reply to let everyone know. A Pong to your Ping. Machines playing a game that none can win and that none will quit.

“This is not a theoretical problem. This has happened about a half-dozen times in the last three months,” said Nickie Kopacka, e-mail administrator at the Center for Computing and Information Technology (CCIT). Kopacka said that at MUSC this problem is bad and getting worse. “With so many more people relying on mailing lists now, the problem is intensified.

The First Circle

“We had an incident one Friday where someone was about to leave for vacation. At the end of the day, he set up a rule for auto-reply, then sent out a message that he would be leaving. Then he got his hat and coat and left. Of course, his mail message was sent to someone who had also set up an auto-reply. By the time the e-mail staff got in on Monday morning, the e-mail system had logged thousands of messages between these two computers. The system was on its knees, barely clinging to life.” To resuscitate it, Kopacka and others had to delete most of the mail in both inboxes as well as most of the mail in the department’s mail server queue. Mail gets deposited in a queue to wait its turn to go through a gateway. When the queue’s disk gets full of Ping-Ponged messages, the queue has to be deleted before the system can be rebuilt.

Three things you can do to avoid this mess: Some form of rules and auto-reply are present in nearly every e-mail program, including the two widely used on campus, GroupWise and QuickMail. But, just because they’re available doesn’t mean they are a good idea. Don’t think of auto-reply as a feature, think of it as a bug—and swat it:

1. Never use “reply to all.” If you get a message from a co-worker, that message may have been carbon copied (cc:) to a list. If you reply to sender, only the co-worker will get the reply. If you reply to all, the co-worker and the mailing list will get the reply. Don’t do it. (In addition to clogging the e-mail system, it could get very embarrassing).

2. Better yet, don’t use auto-reply—ever, never. If you want someone to know you’re out, create a group and send it an e-mail message, tell a co-worker, leave an Audix, or even create a proxy (a sort of alias that allows someone you trust to read and answer your e-mail for you while you’re out). A little planning and a little effort now can save you from a very bad mail day later.

3. At the first sign of trouble, call the Help Desk at 792-9700, and report a mail loop. If e-mail administrators catch the loop early enough, they could save mail that they would otherwise have to delete. What’s a sign of trouble? “If you receive the same message more than once from the same person, especially if that message is obviously an auto-reply, that’s a sure sign of trouble,” Kopacka said.