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The reason for SMTP servers being better off in a proper data-center is not really due to port 25 being blocked at home, it's the entire infrastructure that ass

The reason for SMTP servers being better off in a proper data-center is not really due to port 25 being blocked at home, it's the entire infrastructure that assures reliability, so if your power goes out or your home router decides to die or your ISP is having issues, etc, you would start losing emails right away. EDIT: I understand SMTPs are resilient but it also depends on the type of error they get back, even then it can't be expected that all servers keep retrying for long periods of time or even handle triple bounces. So you 'could' start losing emails right away, is a better way of saying it.

slg 11y ago
It isn't only receiving emails that requires a connection. According to the site, anyone who doesn't use encryption (currently the vast majority of users) will receive a link to your message hosted on the device. That means that most people won't be able to read your emails if your device goes offline.
timboslice 11y ago
Yes, I can only see this being used with an SMTP relay, which seems to kind of defeat the purpose of self hosting
jakobegger 11y ago
Isn't SMTP actually pretty resilient to outages? Typically sending mail servers will retry for hours (or even days) before giving up when a recipient server is down.
- _asciiker_ 11y ago
  Depends on the error the DNS handler 'name.nospy.so' would throw at it.
- McElroy 11y ago
  Yes. This is correct. Once, I had misconfigured my mail server when adding another domain I had bought and it rejected an e-mail. While I was looking into it, I saw in the logs that the sending party had retried after 15 minutes so I corrected my config and waited another 15 and I got the e-mail. Of course, number of retries, if any, and time between attempts will vary between different servers and their configs. Another story I have about e-mail is that another misconfiguration on my part caused mail from me to others to be spam filtered or outright dropped by some receivers. It wasn't until I attempted to send an e-mail to a Debian mailing list that I learned why that was. Their e-mail server was nice enough to reply with the exact reason why they would not accept my mail. I was then able to fix it. (Though I don't remember if they did so in the form of what was said over SMTP and seen by me in logs, or if they bounced the e-mail.)
- bhauer 11y ago
  Yes, it is. Virtually all normal SMTP servers will re-try e-mail delivery several times spaced over at least several hours before rejecting delivery with a notification back to the sender. I have run my own e-mail server for about 17 years, originally from my home and more recently from a data-center where I have co-located my server. Admittedly, when I had my mail server at my home, I would suffer outages long enough to miss e-mails when I needed to do something as severe as work on my home's electrical panel or move. But generally speaking, a momentary glitch in network connectivity would not result in lost e-mail. Since moving my server to a data-center, the only downtime I had was when I needed to replace a disk. As the above paragraph suggests, I am strongly in favor of people running their own mail servers and moving away from the presently-popular centralized Internet, back toward a decentralized model. This device isn't for me, and probably isn't for several of us here, but it's precisely the kind of thing I'd like to suggest to other people who would not otherwise be comfortable running a mail server. I know a lot of programmers who shiver at the thought of managing their own servers, and I feel that's a regretful situation for the Internet at large. It suggests two things: (a) many programmers fear servers, which I don't think is healthy and (b) insufficient R&D has gone into making infrastructure easier to manage. After all (a) is a rational fear given the state of the art in many cases. It can in fact be quite difficult to set up a mail server (although once setup, most are pretty hands-off). It should be much easier to navigate through the settings and have a nearly out-of-the-box configuration that is sane and avoids the most common pitfalls. Aside: Incidentally, I found that even mainstream ISPs like AT&T will unblock port 25 if you call them up and explain you are running your own personal mail server. When I moved to AT&T country, they did exactly that with no questions asked.
  - fche 11y ago
    "Since moving my server to a data-center, the only downtime I had was when I needed to replace a disk." By the way, there exist backup MX services - commercial or self-made, which would give you 100% incoming-mail uptime but without having to move or copy your server to a data center.
    - bhauer 11y ago
      Thanks for the note! I'll definitely keep that in mind next time I evaluate my hosting environment. I expect to switch to a different data center eventually, and that would come in handy.
ryan-c 11y ago
This is somewhat mitigated by the fact that legitimate sending mail servers will retry delivery if the destination server is unavailable. Outbound mail from a home connection may very well have issues being marked as spam due to ip blacklists though.
pjc50 11y ago
.. although the main reason for hosting email at home is that nowhere else is immune to search-and-seizure provisions.
- _asciiker_ 11y ago
  I don't think so, depends on where you live and the laws that apply there. It's probably easier to seize a home server than it is to hassle a company to divulge its contents.
  - pjc50 11y ago
    I think it's the other way round in the US. Conventional email hosting providers are definitely not protected by the 4th. Also for political activists, actually raiding their homes is a dead giveaway whereas leaning on companies can be done quietly.
  - secfirstmd 11y ago
    Or use a Covert Method of Entry approach...
- tiatia 11y ago
  Should be easier to just encrypt all the email. Either by encrypting the HDD or by automatically encrypting all ingoing email with you public GPG key (Saw a perl script for this in a blog)
nadams 11y ago
Most reliable SMTP servers will retry for some amount of time.
lsc 11y ago
eh, it's a security vs. reliability issue. You are right that a home-hosted email is going to be less reliable. Others are right that SMTP is pretty resilient, but not infinitely so. A home mail server, from experience and from the experiences of others, would work okay on receive. You want a static IP (or a static-IP VPN.) at a minimum, and the first thing you need is to make sure you aren't on the dialup-user lists. But that's an outgoing mail issue, not an incoming mail issue. that's the thing, though, the outgoing mail issue, ultimately, is more difficult than the incoming mail issue.
rythie 11y ago
It doesn't seem a big leap to have a small UPS at home ($42 gets you 37mins@20W) or even a rechargable battery in the router and mail server. Further resilence could be handled by partering with another device at a trusted person's house, to act as a backup MX server.
- shubhamjain 11y ago
  Neither does, making Dropbox itself, "trivially by getting an FTP account, mounting it locally with curlftpfs, and then using SVN or CVS on the mounted filesystem. From Windows or Mac, this FTP account could be accessed through built-in software." [1] :) [1]: https://news.ycombinator.com/item?id=8863 https://news.ycombinator.com/item?id=8863
  - rythie 11y ago
    Obviously it needs to be a lot easier than that - the fact that it's difficult right now is the problem. It needs to easy to manage like a smart phone or tablet is.
jlgaddis 11y ago
RFCs dictate that a mail server retry sending when the MX host is unavailable. If the sending mail server doesn't retry then it is the sender's fault if a message is returned undeliverable without retrying at least a few times. The "de facto standard" for retrying was (is?) five days, because that's what sendmail defaulted to for years. Nowadays, many senders don't retry that long (my mail systems are set for 48 hours) simply so that a bounce/undeliverable mail is returned to the sender much sooner. IIRC, there was a certain version of Exchange (I forget which now) that apparently didn't retry and would immediately bounce a message if it was undeliverable on the first attempt, but that was quickly fixed.
- _asciiker_ 11y ago
  Wasn't the "de facto standard" set by QMail back in 1998 ?
  - jlgaddis 11y ago
    Perhaps, it very well could have been. I made an assumption since sendmail was, for the most part, the MTA in those days. Yes, others (including qmail) existed but sendmail was, by far, the most widely used. I, myself, was a sendmail fanboy for years until I eventually moved to postfix in the early/mid-2000s.

slg 11y ago

It isn't only receiving emails that requires a connection. According to the site, anyone who doesn't use encryption (currently the vast majority of users) will receive a link to your message hosted on the device. That means that most people won't be able to read your emails if your device goes offline.

timboslice 11y ago

Yes, I can only see this being used with an SMTP relay, which seems to kind of defeat the purpose of self hosting

jakobegger 11y ago

Isn't SMTP actually pretty resilient to outages? Typically sending mail servers will retry for hours (or even days) before giving up when a recipient server is down.

_asciiker_ 11y ago
Depends on the error the DNS handler 'name.nospy.so' would throw at it.
McElroy 11y ago
Yes. This is correct. Once, I had misconfigured my mail server when adding another domain I had bought and it rejected an e-mail. While I was looking into it, I saw in the logs that the sending party had retried after 15 minutes so I corrected my config and waited another 15 and I got the e-mail. Of course, number of retries, if any, and time between attempts will vary between different servers and their configs. Another story I have about e-mail is that another misconfiguration on my part caused mail from me to others to be spam filtered or outright dropped by some receivers. It wasn't until I attempted to send an e-mail to a Debian mailing list that I learned why that was. Their e-mail server was nice enough to reply with the exact reason why they would not accept my mail. I was then able to fix it. (Though I don't remember if they did so in the form of what was said over SMTP and seen by me in logs, or if they bounced the e-mail.)
bhauer 11y ago
Yes, it is. Virtually all normal SMTP servers will re-try e-mail delivery several times spaced over at least several hours before rejecting delivery with a notification back to the sender. I have run my own e-mail server for about 17 years, originally from my home and more recently from a data-center where I have co-located my server. Admittedly, when I had my mail server at my home, I would suffer outages long enough to miss e-mails when I needed to do something as severe as work on my home's electrical panel or move. But generally speaking, a momentary glitch in network connectivity would not result in lost e-mail. Since moving my server to a data-center, the only downtime I had was when I needed to replace a disk. As the above paragraph suggests, I am strongly in favor of people running their own mail servers and moving away from the presently-popular centralized Internet, back toward a decentralized model. This device isn't for me, and probably isn't for several of us here, but it's precisely the kind of thing I'd like to suggest to other people who would not otherwise be comfortable running a mail server. I know a lot of programmers who shiver at the thought of managing their own servers, and I feel that's a regretful situation for the Internet at large. It suggests two things: (a) many programmers fear servers, which I don't think is healthy and (b) insufficient R&D has gone into making infrastructure easier to manage. After all (a) is a rational fear given the state of the art in many cases. It can in fact be quite difficult to set up a mail server (although once setup, most are pretty hands-off). It should be much easier to navigate through the settings and have a nearly out-of-the-box configuration that is sane and avoids the most common pitfalls. Aside: Incidentally, I found that even mainstream ISPs like AT&T will unblock port 25 if you call them up and explain you are running your own personal mail server. When I moved to AT&T country, they did exactly that with no questions asked.
- fche 11y ago
  "Since moving my server to a data-center, the only downtime I had was when I needed to replace a disk." By the way, there exist backup MX services - commercial or self-made, which would give you 100% incoming-mail uptime but without having to move or copy your server to a data center.
  - bhauer 11y ago
    Thanks for the note! I'll definitely keep that in mind next time I evaluate my hosting environment. I expect to switch to a different data center eventually, and that would come in handy.

ryan-c 11y ago

This is somewhat mitigated by the fact that legitimate sending mail servers will retry delivery if the destination server is unavailable. Outbound mail from a home connection may very well have issues being marked as spam due to ip blacklists though.

pjc50 11y ago

.. although the main reason for hosting email at home is that nowhere else is immune to search-and-seizure provisions.

_asciiker_ 11y ago
I don't think so, depends on where you live and the laws that apply there. It's probably easier to seize a home server than it is to hassle a company to divulge its contents.
- pjc50 11y ago
  I think it's the other way round in the US. Conventional email hosting providers are definitely not protected by the 4th. Also for political activists, actually raiding their homes is a dead giveaway whereas leaning on companies can be done quietly.
- secfirstmd 11y ago
  Or use a Covert Method of Entry approach...
tiatia 11y ago
Should be easier to just encrypt all the email. Either by encrypting the HDD or by automatically encrypting all ingoing email with you public GPG key (Saw a perl script for this in a blog)

nadams 11y ago

Most reliable SMTP servers will retry for some amount of time.

lsc 11y ago

eh, it's a security vs. reliability issue. You are right that a home-hosted email is going to be less reliable. Others are right that SMTP is pretty resilient, but not infinitely so. A home mail server, from experience and from the experiences of others, would work okay on receive. You want a static IP (or a static-IP VPN.) at a minimum, and the first thing you need is to make sure you aren't on the dialup-user lists. But that's an outgoing mail issue, not an incoming mail issue. that's the thing, though, the outgoing mail issue, ultimately, is more difficult than the incoming mail issue.

rythie 11y ago

It doesn't seem a big leap to have a small UPS at home ($42 gets you 37mins@20W) or even a rechargable battery in the router and mail server. Further resilence could be handled by partering with another device at a trusted person's house, to act as a backup MX server.

shubhamjain 11y ago
Neither does, making Dropbox itself, "trivially by getting an FTP account, mounting it locally with curlftpfs, and then using SVN or CVS on the mounted filesystem. From Windows or Mac, this FTP account could be accessed through built-in software." [1] :) [1]: https://news.ycombinator.com/item?id=8863 https://news.ycombinator.com/item?id=8863
- rythie 11y ago
  Obviously it needs to be a lot easier than that - the fact that it's difficult right now is the problem. It needs to easy to manage like a smart phone or tablet is.

jlgaddis 11y ago

RFCs dictate that a mail server retry sending when the MX host is unavailable. If the sending mail server doesn't retry then it is the sender's fault if a message is returned undeliverable without retrying at least a few times. The "de facto standard" for retrying was (is?) five days, because that's what sendmail defaulted to for years. Nowadays, many senders don't retry that long (my mail systems are set for 48 hours) simply so that a bounce/undeliverable mail is returned to the sender much sooner. IIRC, there was a certain version of Exchange (I forget which now) that apparently didn't retry and would immediately bounce a message if it was undeliverable on the first attempt, but that was quickly fixed.

_asciiker_ 11y ago
Wasn't the "de facto standard" set by QMail back in 1998 ?
- jlgaddis 11y ago
  Perhaps, it very well could have been. I made an assumption since sendmail was, for the most part, the MTA in those days. Yes, others (including qmail) existed but sendmail was, by far, the most widely used. I, myself, was a sendmail fanboy for years until I eventually moved to postfix in the early/mid-2000s.