E-Mail 'Life'

Freakish_05 · 26 Nov 2006 at 11:02

Just setting up my own personal mail server

and I got to thinking "what happens to E-Mails if I turn off my server?"

I turned off the box and sent an E-Mail to it. When I turned the box on an hour later, the E-Mail was picked up after a couple of mins.

Does anyone know how long E-Mails last "in the ether"? Would just be interesting to know how long I can leave the server down for before I risk losing important E-Mails.

Cheers.

Felix · 26 Nov 2006 at 11:09

Depending how long the senders email server is set to resend. 72 hours seems to be the longest recommended time.

wasc · 26 Nov 2006 at 13:46

I would say way less than 72 hours.

Most mail servers are configured to bounce the email back to sender after 48 hours (2 days downtime).

However, most mail servers also notify the sender of an email after approx 4 hours of downtime with a "delay" message.

This means if your server is down for 4 hours or more, people sending you mail will have notifications in your inbox to say that emails being sent to you are delayed.

Toytown · 26 Nov 2006 at 23:37

The MTA that we setup has the following default values.

After 8 hours of not being able to connect to the mail server, it will give the original sender a warning, that so far the mail has not been sent, but it will continue trying.

After 4 days it will give the original sender a undeliverable message and will stop trying to send the email.