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At work, we had a mail loop once; a girl from accounting had ordered toner for our printers last thing before she went on vacation and enabled an auto reply on

by krylon 8y ago

At work, we had a mail loop once; a girl from accounting had ordered toner for our printers last thing before she went on vacation and enabled an auto reply on her mailbox. Five minutes after she left the office, the order confirmation arrived, sent from noreply@random.office.supplies.whatever. Her mailbox sent an auto-reply. Our mail server sent her an error message, telling her that her reply had not been delivered. To which her mailbox happily replied with the same auto-reply mail... When I walked into the office on Monday, her mailbox had accumulated around 50,000 of those mails. Fun times.

astrodust 8y ago
I've got a client with an automated ticketing system that loves to get into mail loops with our automated ticketing system. They keep confirming that they've received a reply or update to the previous ticket and a single inquiry can rattle back and forth dozens of times.
- justjash 8y ago
  Yep, had the same thing happen after I implemented an automated mailing process at work. Luckily the ticketing system we hit was slower and I caught it around 6k emails the next day.
- Bluecobra 8y ago
  Is it Jira? If so, I found out the hard way that all you need to take it down is send an emoji in your email.
  - lstamour 8y ago
    If said Jira server is backed my MySQL in the default “UTF8” mode that isn’t actually UTF8. Tell your Jira admins to switch to Postgres or Jira Cloud and all will be well. The same thing happens to Wordpress installs all the time, sadly.
    - isodude 8y ago
      Or update to UTF8mb4 :)
      - ancarda 8y ago
        That may not be enough -- the connection also has to be utf8mb4 as well as other settings: https://mathiasbynens.be/notes/mysql-utf8mb4 https://mathiasbynens.be/notes/mysql-utf8mb4 I have no idea if JIRA supports configuring every aspect of setting up a MySQL connection.
duxup 8y ago
In the early days of "exchange" ... the email client. I discovered auto replies. Very first thing I thought of was "What if two clients have auto replies set?" So naturally I set one up, my cube neighbor set one up. I sent an email to my cube neighbor ... and fairly quickly email was down company wide for a good afternoon.
- deleted 8y ago
  [deleted]
- peteradio 8y ago
  Why didn't anyone say anything when they were implementing this feature. It seems kind of obvious, not even with hindsight.
  - duxup 8y ago
    IIRC rules such as out of office (I'm not sure "rules" really existed). Were client side only... the server didn't have the option (or at least it wasn't automatic) to evaluate bad rules / out of office.
  - bmn__ 8y ago
    Mail loops should not exist in theory, see https://tools.ietf.org/html/rfc3834#section-2 https://tools.ietf.org/html/rfc3834#section-2 But when programmers make RFC ignorant software, then all bets are off. Don't be that guy.
gregmac 8y ago
I once (accidentally) setup a mail group with itself as a member. Everything was fine until the first message came in, and a few minutes later I hear "Uh, why do I have 5,000 new emails?" "Woah, I have 9,000", "Oh, mine is at 15,000 now!". I don't remember what it got up to before we managed to get into the now-very-slow mail server to fix it, but it was in the hundreds of thousands. Luckily it was only internal mailboxes.
- leephillips 8y ago
  The only group of mail groups that you should use is the one that only has mail groups that do not have themselves as a member.
  - xpil 8y ago
    After reading this statement like 5 or 6 times I am still not sure whether I grok it or not. Would put it on a sticker though.
    - chopin 8y ago
      I think it's akin to "the set of all sets which do not contain themselves". EDIT: My favorite is more "the town barber who shaves all men in town who do not shave themselves".
rement 8y ago
Reminds me of this TED talk https://www.youtube.com/watch?v=Dceyy0cX6J4 https://www.youtube.com/watch?v=Dceyy0cX6J4

by krylon 8y ago

astrodust 8y ago

I've got a client with an automated ticketing system that loves to get into mail loops with our automated ticketing system. They keep confirming that they've received a reply or update to the previous ticket and a single inquiry can rattle back and forth dozens of times.

justjash 8y ago
Yep, had the same thing happen after I implemented an automated mailing process at work. Luckily the ticketing system we hit was slower and I caught it around 6k emails the next day.
Bluecobra 8y ago
Is it Jira? If so, I found out the hard way that all you need to take it down is send an emoji in your email.
- lstamour 8y ago
  If said Jira server is backed my MySQL in the default “UTF8” mode that isn’t actually UTF8. Tell your Jira admins to switch to Postgres or Jira Cloud and all will be well. The same thing happens to Wordpress installs all the time, sadly.
  - isodude 8y ago
    Or update to UTF8mb4 :)
    - ancarda 8y ago
      That may not be enough -- the connection also has to be utf8mb4 as well as other settings: https://mathiasbynens.be/notes/mysql-utf8mb4 https://mathiasbynens.be/notes/mysql-utf8mb4 I have no idea if JIRA supports configuring every aspect of setting up a MySQL connection.

duxup 8y ago

In the early days of "exchange" ... the email client. I discovered auto replies. Very first thing I thought of was "What if two clients have auto replies set?" So naturally I set one up, my cube neighbor set one up. I sent an email to my cube neighbor ... and fairly quickly email was down company wide for a good afternoon.

deleted 8y ago
[deleted]
peteradio 8y ago
Why didn't anyone say anything when they were implementing this feature. It seems kind of obvious, not even with hindsight.
- duxup 8y ago
  IIRC rules such as out of office (I'm not sure "rules" really existed). Were client side only... the server didn't have the option (or at least it wasn't automatic) to evaluate bad rules / out of office.
- bmn__ 8y ago
  Mail loops should not exist in theory, see https://tools.ietf.org/html/rfc3834#section-2 https://tools.ietf.org/html/rfc3834#section-2 But when programmers make RFC ignorant software, then all bets are off. Don't be that guy.

gregmac 8y ago

I once (accidentally) setup a mail group with itself as a member. Everything was fine until the first message came in, and a few minutes later I hear "Uh, why do I have 5,000 new emails?" "Woah, I have 9,000", "Oh, mine is at 15,000 now!". I don't remember what it got up to before we managed to get into the now-very-slow mail server to fix it, but it was in the hundreds of thousands. Luckily it was only internal mailboxes.

leephillips 8y ago
The only group of mail groups that you should use is the one that only has mail groups that do not have themselves as a member.
- xpil 8y ago
  After reading this statement like 5 or 6 times I am still not sure whether I grok it or not. Would put it on a sticker though.
  - chopin 8y ago
    I think it's akin to "the set of all sets which do not contain themselves". EDIT: My favorite is more "the town barber who shaves all men in town who do not shave themselves".

rement 8y ago

Reminds me of this TED talk https://www.youtube.com/watch?v=Dceyy0cX6J4 https://www.youtube.com/watch?v=Dceyy0cX6J4