Email fate on server down ?

[siliconmike]

Hi,

What happens to an email sent to a server if that server is down ? I
mean, does the sender get a failed to deliver message ? Or does it get
lost without the sender's knowledge?

(Apologies to post this question which is really not relevant to perl.
Unfortunately I searched through google groups but could not find a
relevant active group for this post.)]

Regards,
Mike

 

[Gregory Toomey]

Hi,

What happens to an email sent to a server if that server is down ? I
mean, does the sender get a failed to deliver message ? Or does it get
lost without the sender's knowledge?

(Apologies to post this question which is really not relevant to perl.
Unfortunately I searched through google groups but could not find a
relevant active group for this post.)]

Regards,
Mike

What happen when email is sent to you and you're not online? Its queued for
later retrieval.

With store-and-forward Mail Transfer Agents (postfix etc), they usually
retry sending for at least few days.
http://en.wikipedia.org/wiki/Store_and_forward

gtoomey

 

[siliconmike]

Yes, but say if hundreds of users are sending email to say
(e-mail address removed) and if say, the server hosting whatever.com is down at
those times, then do you assert that *all* of those users would get a
'failed delivery' message ?

Mike

 

[siliconmike]

add this to my previous question:

"failed delivery message ? (assuming that they're not using store & fwd
mail transfer agents)

 

[Gregory Toomey]

Yes, but say if hundreds of users are sending email to say
(e-mail address removed) and if say, the server hosting whatever.com is down at
those times, then do you assert that *all* of those users would get a
'failed delivery' message ?

Mike

It depends (thats not much help).

Some may be lost, some may be requeued, depending on the config of the
sending mail delivery agent.

gtoomey

 

[Chris Mattern]

Hi,

What happens to an email sent to a server if that server is down ? I
mean, does the sender get a failed to deliver message ? Or does it get
lost without the sender's knowledge?

(Apologies to post this question which is really not relevant to perl.
Unfortunately I searched through google groups but could not find a
relevant active group for this post.)]

comp.mail.misc seems to fit the bill to me...

However, since you did make the effort, I will say the normal action
is that that your MTA (mail transfer agent) keeps trying. You'll
generally get a mail message every few hours saying that your mail
couldn't be delivered but it's still trying. After some defined
period (usually several days) it gives up, and you get an email message
saying it gave up.


--
Christopher Mattern

"Which one you figure tracked us?"
"The ugly one, sir."
"...Could you be more specific?"

 

[Chris Mattern]

Yes, but say if hundreds of users are sending email to say
(e-mail address removed) and if say, the server hosting whatever.com is down at
those times, then do you assert that *all* of those users would get a
'failed delivery' message ?

Well, yes. Because it's not the server giving out those messages.
The server isn't doing *anything*, remember--that's the problem! All
those users get messages *from their own machines* saying they couldn't
get in but are still trying (or have given up, if that's the case).

--
Christopher Mattern

"Which one you figure tracked us?"
"The ugly one, sir."
"...Could you be more specific?"

 

[chris-usenet]

(Apologies to post this question which is really not relevant to perl.
Unfortunately I searched through google groups but could not find a
relevant active group for this post.)]

comp.mail.misc is pretty active.

 

[chris-usenet]

Yes, but say if hundreds of users are sending email to say

(e-mail address removed) and if say, the server hosting whatever.com is down at
those times, then do you assert that *all* of those users would get a
'failed delivery' message ?

Some may be lost, some may be requeued, depending on the config of the
sending mail delivery agent.

The whole point of SMTP was supposed to guarantee that no email would
ever be lost. Provided the mail headers were correct, then unless you got
a delivery error you could assume it had been delivered. Unfortunately
anti-spam and anti-virus systems (well, the reasons for their existence)
have put paid to that guarantee.

Note that I'm excluding mail user agents (Outlook, Thunderbird, Eudora,
et al) from this "guarantee". They can reasonably assume that a mail
host is always available.

Mail transport agents go to great lengths to ensure that a piece of email
is not considered as "accepted" until it has been written to non-volatile
storage (i.e. disk).

If a mail delivery host is unavailable then the sending host will
queue the traffic for a number of hours or days. Usually a four hour
delay will cause a response to be sent to the sender warning about the
delivery delay.

In order to help load-balance mail delivery systems, alternate systems
can be configured to accept email for a host on its behalf. You can
find out about such mail exchangers by looking in the DNS for "MX"
records. The lower numbered systems are higher priority acceptors.

Follow-ups set to comp.mail.misc this definitely does not belong in
comp.lang.perl.misc.

Chris

 

[Peter Scott]

(Apologies to post this question which is really not relevant to perl.
Unfortunately I searched through google groups but could not find a
relevant active group for this post.)]

I went to groups.google.com, typed in 'mail', and the first thing it said was
that there were 770+ groups related to 'mail'. Clicking on that number gave
a list ordered by topic, with 50 under 'Computers'. Clicking on that gave a
list of groups with descriptions, the 5th one being:

comp.mail.misc
Group description: General discussions about computer mail.
Category: Computers
Usenet, public

 

[Tad McClellan]

(Apologies to post this question which is really not relevant to perl.
Unfortunately I searched through google groups but could not find a
relevant active group for this post.)]

I went to groups.google.com, typed in 'mail', and the first thing it said was
that there were 770+ groups related to 'mail'. Clicking on that number gave
a list ordered by topic, with 50 under 'Computers'. Clicking on that gave a
list of groups with descriptions,

I did that too.

Then I made a scorefile entry. :-(