[Cialug] Email server

[Nicolai]

On Sat, Apr 29, 2017 at 01:01:18PM +0000, Kyle H wrote:
> I'll run my own postfix and have my own email on my own server on my
> own domain! I've always wanted to do that. :)

I know you've already decided to get a VPS for this, which is the right
choice, but I just wanted to expand on some ideas presented here.

1) Someone who runs a mailserver at home could receive mail, but would
have serious difficulty _sending_ mail, as Mediacom's non-business
customer networks are listed in Spamhaus PBL:

 "The Spamhaus PBL is a DNSBL database of end-user IP
  address ranges which should not be delivering
  unauthenticated SMTP email to any Internet mail
  server except those provided for specifically by an
  ISP for that customer's use."

https://www.spamhaus.org/pbl/

You can verify this with your own IP address.  If it's 192.0.2.10, then
reverse the octects and do a DNS query like this:

dig 10.2.0.192.pbl.spamhaus.org

It should be listed and given the IP address 127.0.0.11.

2) Regarding reverse DNS, there are two things to say: first, in this
case, Mediacom automaticallly provides matching forward and reverse DNS
(called FCrDNS).  This is required but insufficient to reliably send mail,
as some receivers demand that you have rDNS that isn't generic looking.
And 1-2-3-4.client.mchsi.com is definitely generic.

3) Every time the person's IP address changes they'd have to scramble.

So yeah, you've made the right choice to get a VPS.  You can get them
for as low as $1/mo (ChicagoVPS), but you can have a better one for
$2.50/mo (VULTR).

Also, you won't have the hassle of running a mailserver on or through
your router/firewall, increasing your chance of getting a successful
working setup.

Modern mailservers have lots of moving parts and the ecosystem is
unhealthy due to centralization, years of spam, and certain spam
countermeasures which cause great fragility.

Nicolai