Moronic Mail Autoresponders (A FAQ From Hell)
This FAQ is first and foremost a classic example of
trying to be cute while completely alienating the
intended audience. I wrote it that way
(including this paragraph
Shirley, you must have sent mail to someone and received one
of the following annoying types of response:
and now I'm too lazy and/or overworked to fix it.
Be patient with all the sarcasm and, uh, "attitude";
there really is some useful
I know, "Don't call me Surely."
Bounce messages are often confusing to newbies, because there's so
much fluff there and nobody ever really told them how to deal with
delivery problems in the real world. However, that's not what we
are interested in here. For knowledgeable users, properly generated
and formatted bounce messages are a useful way to find out
about a problem and react in the appropriate way
(if it's a transient error, just wait and see;
call on the phone instead if there seems to be a major problem
and you want your mail to get through, etc).
Instead, we are getting annoyed by bounce messages which should never
have been sent in the first place (or at least not sent where they
were sent to).
"I use this nifty email program (which typically isn't even free
software) and look, it allows me to send autoreplies like this one.
I just wanted to say 'egads'. Thank you for listening."
Do I look like I care?
"Your mail has been delivered to my mailbox and I will read it
as soon as I can."
Astonishing. Are you sure it was really meant for you?
If your mail system is so unreliable that delivery of a message is
considered a major event, you should be sending this notification
to your postmaster, not to me. (If you use some buggy proprietary
mail system inside your company, such as cc:Mail or MS Exchange,
I can understand that delivery of a message is considered special.
But that's still your problem, not mine.)
Normally, I would expect a bounce if it wasn't
delivered. And/or am I supposed to believe that you normally don't
read your mail?
"A client of ours subscribes to our r4d k00l newbie mail service
and you sent him a message, so we thought that would make it okay
for us to spam you. Perhaps we'll be selling your address to a
company which specializes in sending unsolicited commercial email,
Eat my shorts. This is so obnoxious.
And do you think they rate-limit this dreck? No, you
get one "friendly reminder" for each message you send
to this person.
Here's a (reassuringly short, for now) list of domains which do this
in case you would like to block their notices:
This is available as a separate text file, too. Click here to view
(I would appreciate help with locating other domains which should
be listed here.
Please get in touch
if you have that sort of information.)
I was also recently exposed to a service whose user documentation
suggests you spam all your friends with an ad for this likewise r4d k00l
new email feature you just got subscribed to so they can join the fun, too.
It probably makes sense to respond to this kind of stuff with a spam
complaint to the ISP of the user in question ...
"I am out of the office and will be back and read my mail on
Friday the 13th."
This is annoying under the following circumstances:
You never knowingly sent mail to this guy in the first place.
The response contains no trace of your original message, so there's
no way to tell what this is in response to.
It gets sent to a mailing list, or you get it apparently in response
to something you sent to a mailing list. See below for more on this
You receive a big batch of these notices, all from the same address.
It should be easy to deduce the following:
A good autoresponder should never reply to mailing list mail.
(Just think what would happen if two morons signed up to the same
mailing list at about the same time, and their email autoresponders
started bombing each other via the list. It's a spectacular, but not
very pretty sight, for anyone on the mailing list.)
A good autoresponder should always contain information about the message
it's responding to. Ideally, the
Subject header of the
response should preserve at least part of the original Subject (perhaps
with a prefix such as Autoresponse:) and the In-Reply-To and/or References:
should contain the Message-Id of the message it is responding to.
While we're at it, here are a few more rules which aren't really specific
to this particular case:
Autoresponses should always contain the header
Notice the spelling of "prec-e-dence". In particular, count the number of n:s
(and a:s and s:es, if you're totally agraphic and/or from the United States).
This will prevent well-tempered mail programs from generating bounce
messages for these. If the recipient can't be reached, the autoresponder
message is simply discarded.
Autoresponders should take care to not respond to bounce messages
(or mailing list messages, or other well-behaved autoresponders).
A good thing to check against is the presence of that same
Precedence header, and if its value is
(For what it's worth, the meaning of the
in practice is that it affects Sendmail so that messages identified as
less important get moved back in the queue under high load. On today's
machines, that kind of load would be the exception rather than the norm.
Those three values plus
special-delivery are the only ones
which have any meaning to Sendmail.
first-class is also
nominally recognized, but is equal to the case of no
header. [If other MTAs have different semantics for this header, that
would be a serious issue, and worth including here. If you have information
about other systems,
please let me know.])
The documentation for Procmail contains a good
regular expression for other things to watch out for
^FROM_DAEMON. If you don't read regular expressions,
you'll need serious help.)
"In an effort to avoid receiving spam, I ask you to key all your mail to
me using the following secret word in the Subject: line:
This is barely tolerable if the autoresponder is otherwise set up correctly,
but typically, you have some or all of the problems listed above (multiple
notices, responses to mail you didn't particularly want to send to this
person in the first place [perhaps you sent them to a mailing list],
no trace of what the autoresponder is responding to).
There is a standard for bounce messages,
which only a handful of MTAs currently implement.
If bounce messages could be more standardized, it would be easier for
developers of MUAs to try to present them to the user in meaningful ways.
If you think that this problem will solve itself when Microsoft has bought,
monopolized, and bastardized all MTAs worth their salt (because
then we will all be one big happy family who are all using
Microsoft products), think again. They can't even follow their own
I've been too lazy to finish this section. If anybody with a good
knowledge of RFC822 and related sources would like to fill me in,
please do get in touch.
"Your message to email@example.com could not be delivered because
this user doesn't exist at phish.org"
Great, I never sent mail to Phred. Probably I never even sent
anything to anyone at
Moreover, in the body of the bounce,
we find a message I sent to a mailing list some time ago.
But I can't do anything about this -- I didn't subscribe Phred,
I don't know where he moved, I can't unsubscribe him, and frankly
<blink>I don't care</blink>
whether he gets this list or not.
This is a frequent configuration error with mailing lists
(actually, it's a bug, dammit, not a configuration error).
The list should set the envelope sender on outgoing mail to the
list's owner (typically an alias like
list-request@site) so that s/h/it can take care
of unsubscribing illegal addresses etc. without interfering with
normal list operation. (By the way, a unique envelope sender also
makes it much more convenient to unambiguously determine whether
a message arrived via the list or perhaps as a private personal
firstname.lastname@example.org is not known to
the program which handles mail for
Please get in touch with
if you think that's strange."
This is a problem with older versions of Post.Office and I believe
Netscape's mail server. The bounce includes a lengthy explanation
for the newbie postmaster about what could be wrong. But why is that
being sent to the person whose message is not getting through?
postmaster just as an example here, although it's
typical for this error to occur on the
For what it's worth, the
must work properly for every system which is
handling mail on the Internet. See
If you get one of these, it's reasonable and responsible to look
up the domain in question in
whois and mail the
administrative contact(s) for the domain about this problem (as well
as possibly the technical contact and the upstream provider).
lists some standard addresses besides
which should be implemented at modern sites.
This codifies e.g.
webmaster as the standard address
for responding to problems with web pages,
spam complaints, etcetera.
email@example.com is not known to
the program which handles mail for
Please get in touch with
if you think that's strange."
A variant of the previous case. This would be funny if it wasn't so
totally technically inept and, well, moronic.
"551 <firstname.lastname@example.org> ... we do not relay"
We're not attempting to relay, we're attempting to get in touch with
your freaking local postmaster. See previous cases.
"MS Exchange could not deliver mail to Administrator 9188.8.131.52
ybpnyubfg 917.45.986.14 njnl.yvatfbsg.sv njnl 184.108.40.206 urp barf
You would receive this from a domain you have never heard about,
but by examining headers in the bounced message and querying DNS,
you find that you tried to mail not one but two users in a domain
which this machine is MXing for.
But do you think you are entitled to know which one is undeliverable?
Nooo. It just reports which end point it couldn't reach. This is
basically the same as the Friday the 13th example, although
it's much more annoying because this time, you really knowingly
tried to mail someone, and it didn't work out, and now, you'd probably
like to know who you tried to contact, so you can e.g. call them on the
I have $5 here which says, if you tried to mail a user in a domain
and Cc: the postmaster, and get this response, the address which
bounced will be the postmaster one.
fun little chart which comes with formail
is a reasonable approximation (if you look at the chart which describes
the behavior with the
The documentation isn't very explicit about it, but it's a slighly
whimsical but pragmatic compromise between obeying the letter of the
various standards out there and what works in practice.
For what it's worth, at least one fairly knowledgeable person
insists that the envelope sender of whatever triggered the autoresponder
should be the recipient for all automatically generated mail.
(Keith Moore in
By contrast, the following types of responses actually tell
you something you might need to know:
I happen to think it's a violation of RFC822, but it's a somewhat
The author of this FAQ has a strong preference towards Procmail,
but there are of course other ways to make your own moronic
autoresponder. The author's page of
contains a section near the end with pointers to information
about other mail filtering systems (even for half-assed excuses
for an operating system like Windows, with my condolences).
"I am extremely overworked, and will probably not be able to respond
within what is considered a normal time frame (something like 3 days).
I'll hopefully be able to get back to you after Christmas 2003."
Okay, we'll know to wait patiently for a reply from this guy.
His autoresponder should not send more than one of these notices to
the same address in, say, a week. And did I mention it should not
respond to mailing list mail?
"Thank you for contacting the Department department of So And So, Inc.
We're busy beavers here, but rest assured that we are dealing with
your complaint/whatever. We don't usually send replies if it's a matter
of a simple bug report or something; we simply fix the bug and that's it.
If a reply is warranted, our staff will get back to you."
This tells you, essentially, that they will deal with the matter and
not send you a personalized reply. This automatic reply (frequently
affectionately referred to as "ignorebot") will do. This is pretty
much the standard you get nowadays when you send a spam complaint or a
service request to an ISP, for example.
The autoresponder might also tell you something about the type of
information they will need in order to be able to resolve your
issue, so you can follow up with this information if you didn't
include it in your original message. Perhaps they will also issue you
a ticket number to make it easier (kind of) for you to get directly in
touch with the staff member who is dealing with your problem report
if you need to follow up.
In the future, this section should probably be self-contained,
and contain information about
If you feel like commenting on this FAQ, or submitting some
changes, feel free to
(sorry about the form -- you know, defense against the morons).
- MUAs which offer autoresponder services
- MDAs which offer autoresponder services
- MTAs which offer autoresponder services
- Other programs which offer autoresponder services
- Other services which offer autoresponder services
(such as Hotmail-type services
[I don't think Hotmail has autoresponders though])
For now, this is basically cannibalized out of my bookmarks file.
The following sites should be interesting:
Dan Bernstein's site
There's a good annotated index of mail header fields
and recommendations for their use, with pointers to
RFCs where available. Definitely bookmark stuff.
The Internet Mail Consortium
A bit too much of "something for everyone" but the information
you want is probably there somewhere.
Eli the Bearded's Mail Addressing FAQ
Tangential to the topic of this FAQ, but worth a look
for other reasons.
Dmoz: Computers: Internet: Protocols: Mail
... and perhaps also
Servers: Mail: Autoresponder Services
I have a
bigger link collection
as part of the Procmail FAQ I maintain.
The use of the
If you happen to know somebody at Microsoft who works on their
mail applications and knows almost all the letters of the alphabet,
make them read this. (You might also want to inform them about
the existence of documents called "RFCs".)
is explained somewhat on the
There are also practical usage notes on a good number of other header fields.
The same goes for anyone else who needs this information.
However, you are not allowed to charge for this information,
or claim that you wrote it. Because I did.
If you link to this page, please use this "official" URL
instead of whatever it is that your moronic browser wants to
make you think you are currently viewing:
Thanks. Hope this helps. Where am I?
$Id: autoresponder-faq.prep,v 1.20 1999/08/24 10:49:17 reriksso Exp $