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Mail self-hoster here. There's an additional wrinkle, which luckily you may never encounter in the public cloud space: in addition to typically being unable to

Mail self-hoster here. There's an additional wrinkle, which luckily you may never encounter in the public cloud space: in addition to typically being unable to _send_ mail from residential Internet connections, it's many times also not possible to _receive_ mail on a residential Internet connection. On the outbound side, many accepters of mail will deny mail from SMTP servers on a residential IP address, as provided by the Spamhaus Policy Block List (https://www.spamhaus.org/pbl/ https://www.spamhaus.org/pbl/) or equivalent. Unfortunately, there's not much one can do to get off this list - ISPs self-publish their own residential IP space onto it. In order to self-host from home, business-class service or higher is in order. Or, again, use the public cloud, and hope your compute instance's IP isn't on some other block list. On the inbound side, though, many ISPs block inbound port 25. Since that's the agreed-upon port for mail receipt, there's no real way around this. Several times while I self-hosted off residential, I was able to call Comcast support and ask for the ban to be lifted, but not before fighting through several layers of level one support asking me to configure my mail client differently. The real kicker, though, is any time my modem was rebooted (I owned my modem, too!), I had to call in and request it _again_. My (very small local) ISP in upstate New York also performed this blocking, but _would not_, in the face of any complaining, lift the block.

jamal-kumar 4y ago
Ohhhhhh there's a way! Pure End-To-End SMTP sending and receiving! It involves some pretty interesting tomfoolery using IPSEC tunnels on a pure OpenBSD setup, but even works when you don't have a fixed IP. https://www.exoticsilicon.com/jay/smtp_via_ipsec_tunnels https://www.exoticsilicon.com/jay/smtp_via_ipsec_tunnels
- guiambros 4y ago
  "In this guide, Jay shows us how to setup an IPSEC tunnel between a local machine running OpenBSD, and a remote VM hosted at OpenBSD Amsterdam..." A tunnel to a vm hosted on a cloud provider is far from "running SMTP servers on a residential IP address" that OP was referring to.
  - jamal-kumar 4y ago
    If you're not as impressed by end to end SMTP as I am then I feel you're missing out! Oviously you need domains with RDNS and everything to point to a public IP address for relay, but if it's a really cheap VPS that's pretty cool. Sure is a LOT lighter than running a full mail server with three or four protocols to get things right and keeping that up to date and exposed to the public.
throwawayboise 4y ago
In the ISP's defense, 99% of the time an SMTP sender in their residential address space is going to be a compromised device sending spam. It's pretty understandable that they would just decide that pissing off the relatively very few customers who want to run their own mail servers is a cost they are willing to accept.
- koolba 4y ago
  I bet it’s more than 99% too. Even amongst the tech savvy, there’s special level of dedication to run your own mail infrastructure. It’s like one in 10-25K.
  - jjav 4y ago
    No special level of dedication needed. I'm one of the many who run my own email infrastructure and it is very little work. Nearly none, really, aside from initial setup. However, I don't run it from home over residential ISP connection.
    - cm2187 4y ago
      Still, it’s not trivial to set up, particularly if you want TLS connections, monitoring brute force attacks, etc.
      - necovek 4y ago
        Not the poster you are replying to, but as a self-hoster (on a static residential IP though) I don't necessarily care about brute forcing that doesn't completely kill off my connection (I've actually got two residential connections used as fail-over: 1Gbit/200Mbit + 500Mbit/50Mbit, though set up as round-robin on the incoming domains [same priority]). I mostly run the mail for my family and myself, so the attack surface is reasonably small. My network mostly only dies when one of the ISP-provided modems slows down too much without actually killing off the actual connection (so pings seem to keep working from my OpenWRT router to detect dead connections), which requires resetting that modem (happens only every few months, rare enough for me to bother debugging it: it's usually my dad who pings me early the next morning that his email is not working :)).

jamal-kumar 4y ago

Ohhhhhh there's a way! Pure End-To-End SMTP sending and receiving! It involves some pretty interesting tomfoolery using IPSEC tunnels on a pure OpenBSD setup, but even works when you don't have a fixed IP. https://www.exoticsilicon.com/jay/smtp_via_ipsec_tunnels https://www.exoticsilicon.com/jay/smtp_via_ipsec_tunnels

guiambros 4y ago
"In this guide, Jay shows us how to setup an IPSEC tunnel between a local machine running OpenBSD, and a remote VM hosted at OpenBSD Amsterdam..." A tunnel to a vm hosted on a cloud provider is far from "running SMTP servers on a residential IP address" that OP was referring to.
- jamal-kumar 4y ago
  If you're not as impressed by end to end SMTP as I am then I feel you're missing out! Oviously you need domains with RDNS and everything to point to a public IP address for relay, but if it's a really cheap VPS that's pretty cool. Sure is a LOT lighter than running a full mail server with three or four protocols to get things right and keeping that up to date and exposed to the public.

throwawayboise 4y ago

In the ISP's defense, 99% of the time an SMTP sender in their residential address space is going to be a compromised device sending spam. It's pretty understandable that they would just decide that pissing off the relatively very few customers who want to run their own mail servers is a cost they are willing to accept.

koolba 4y ago
I bet it’s more than 99% too. Even amongst the tech savvy, there’s special level of dedication to run your own mail infrastructure. It’s like one in 10-25K.
- jjav 4y ago
  No special level of dedication needed. I'm one of the many who run my own email infrastructure and it is very little work. Nearly none, really, aside from initial setup. However, I don't run it from home over residential ISP connection.
  - cm2187 4y ago
    Still, it’s not trivial to set up, particularly if you want TLS connections, monitoring brute force attacks, etc.
    - necovek 4y ago
      Not the poster you are replying to, but as a self-hoster (on a static residential IP though) I don't necessarily care about brute forcing that doesn't completely kill off my connection (I've actually got two residential connections used as fail-over: 1Gbit/200Mbit + 500Mbit/50Mbit, though set up as round-robin on the incoming domains [same priority]). I mostly run the mail for my family and myself, so the attack surface is reasonably small. My network mostly only dies when one of the ISP-provided modems slows down too much without actually killing off the actual connection (so pings seem to keep working from my OpenWRT router to detect dead connections), which requires resetting that modem (happens only every few months, rare enough for me to bother debugging it: it's usually my dad who pings me early the next morning that his email is not working :)).