Running a mail server is easy, providing a mail service is HARD. Deliverability is really difficult. Being online all the time to make sure you're always recieving email is hard.
I was constantly plagued by worry that the important email I sent never actually arrived, or the important email I was waiting for had been sent but I never actually got it.
Just because it's in the RFC does not mean it will be obeyed.
I tried running postgrey - a system that rejects senders it doesn't recognise, tells them to "try again in a minute", and accepts the second email. The theory being that spammers rarely check for these responses because they operate on a "fire and forget" basis. In reality it didn't work because lots of email services didn't correctly respond to the "try again in a minute" response - which is in the RFC!
Maybe it's an extreme example. You expect an SMTP server not to be up all the time, you don't expect them to randomly reject mail and ask you to try again later, but you get my point. It just adds to the stress/worry. I found myself default to Gmail a lot of the time for this reason.
I don't know if it still exists, but I'm sure it could be found or would make a good service. I seem to recall paying about $10/mo to a company that would provide secondary MX services. They did no delivery/webmail etc, it was purely "You can list us as a secondary MX and when yours is online we'll forward".
* Mail you want to receive:
Your server can be down for a few days (if I remember correctly, 5 days, according to postfix defaults) and still receive all emails when it goes up again. More downtime and the senders will receive permanent error bounces.
If you fear longer server downtimes, you also have the option of secondary MX servers.
* Mail you send:
Just display the mail log (/var/log/mail.info) and see if you get 250 OK responses when you submit messages. What happens next is not your responsibility anymore (except for spam filter rules of course, you need spf, dkim...)
I configured my server once, over two years ago. I logged in on root once again, when I run out of disk space, I made a cron job to remove oldest logs monthly. It's centos6 and it works. Should I care more about it? Anything I should pay attention to?
Comments
Running a mail server is easy, providing a mail service is HARD. Deliverability is really difficult. Being online all the time to make sure you're always recieving email is hard.
I was constantly plagued by worry that the important email I sent never actually arrived, or the important email I was waiting for had been sent but I never actually got it.
SMTP requires the sender to retry delivery if the destination is unreachable.
https://tools.ietf.org/html/rfc5321#section-4.5.4.1
Just because it's in the RFC does not mean it will be obeyed.
I tried running postgrey - a system that rejects senders it doesn't recognise, tells them to "try again in a minute", and accepts the second email. The theory being that spammers rarely check for these responses because they operate on a "fire and forget" basis. In reality it didn't work because lots of email services didn't correctly respond to the "try again in a minute" response - which is in the RFC!
Maybe it's an extreme example. You expect an SMTP server not to be up all the time, you don't expect them to randomly reject mail and ask you to try again later, but you get my point. It just adds to the stress/worry. I found myself default to Gmail a lot of the time for this reason.
I don't know if it still exists, but I'm sure it could be found or would make a good service. I seem to recall paying about $10/mo to a company that would provide secondary MX services. They did no delivery/webmail etc, it was purely "You can list us as a secondary MX and when yours is online we'll forward".
* Mail you want to receive: Your server can be down for a few days (if I remember correctly, 5 days, according to postfix defaults) and still receive all emails when it goes up again. More downtime and the senders will receive permanent error bounces.
If you fear longer server downtimes, you also have the option of secondary MX servers.
* Mail you send: Just display the mail log (/var/log/mail.info) and see if you get 250 OK responses when you submit messages. What happens next is not your responsibility anymore (except for spam filter rules of course, you need spf, dkim...)
Great, now I've got to run TWO mail servers. That'll decrease my anxiety levels. ;D
I configured my server once, over two years ago. I logged in on root once again, when I run out of disk space, I made a cron job to remove oldest logs monthly. It's centos6 and it works. Should I care more about it? Anything I should pay attention to?