Search Again: Re: Mail Loops From: Danny Grizzle Date: Monday, June 22, 1998 Time: 2:00:00 pm >What, exactly, is a "mail loop"? A mail loop is not DNS related. A loop can occur when there is automatic generation of e-mail, such as auto-forwarding, an auto-responder, or a mail list server. Say two people are partners; for example Elton John and Bernie Taupin. They agree to share everything. So Elton sets up his e-mail client to forward a copy of everything to Bernie, and Bernie does the same, sending everything to Elton. A mail loop exists. It does not matter if they use seperate domains and ISPs or the same. Once mail is sent to either, the loop gets going, and they auto reply to each other forever, or at least until a mail server's hard drives fill up. Programmers call this an infinite loop. Hold a microphone up to the PA loudspeaker and you get an ear-shattering howl, analog feedback. That's what a mail loop is. Very painful. >I just added a new domain making every DNS >entry virtually identical to an exising domain (that works just fine) >except that [existing domain name] was replaced by [new domain name]. Are you auto forwarding the old domain to the new? Does the new domain have an autoreply... even to things auto forwarded from the old? If so, there is a mail loop. It is especially easy to get a mail loop going when a list server is involved because so many of their functions generate an automatic response. Another place to look is "role" accounts. For instance, if you send wildcard matches or generic addresses (info@yourcustomer.com, sales@yourcustomer.com) to a role account (secretary@yourcustomer.com), and that account generates an auto-response, then there is the potential for trouble. I highly recommend adding a product called MailBurst which vastly enhances EIMS mail server functionality. It also adds potential for mail loops. I once generated a couple of thousand e-mail messages to a secretary's mail box. She had to delete them manually. Lucky we caught this loop before the weekend. http://www.dantowitz.com >I should add that InterNIC has not yet been updated to reflect this >domain's new home (the change will be going in today). Irrelevant. Mail loops occur on an account-by-account basis, unrelated to a domain, although you could create a loop for an entire domain during a changeover of domain names if you were somehow automatically generating e-mail, such as forwarding from the old to the new. One final story on loops. I once called the Fort Worth Star-Telegram (newspaper) at 5:01 on a Friday afternoon with an emergency change on an ad. I got my rep's voice mail, said "If you need immediate assistance, press "0" for help". She had forward her phone to the next cubicle. I got that person's voice mail. I had a million things on my mind, continued to work absent mindly as I kept pressing "0" on every voice mail for a live operator. About twenty minutes later, I realized I was hearing the same names again. My rep's message never repeated (the familiar name would have clued me in sooner). It turns out that about two dozen people at the newspaper had their voice mail forwarding in a giant loop. I was livid at the time, and it still doesn't seem funny even 5 years later... Danny Grizzle

Messages In This Thread: Mail Loops by Marconi on Jun 22, 1998 at 12:19:00 pm Re: Mail Loops by Danny Grizzle on Jun 22, 1998 at 2:00:00 pm