On Sun, 29 Dec 2024 17:51:34 +0000 (GMT) Tim Woodall <debianu...@woodall.me.uk> wrote:
> On Sun, 29 Dec 2024, mick.crane wrote: > > > hello > > I'm not really understanding the internet. > > Can I do my own SMTP server and send mail off to the right place > > without having the device open to random internet connections? > > > > mick > > > Yes, but in practice many places won't accept mail from most home IPs > even if you can get the reverse DNS set up correctly - which most ISPs > don't support. > > So except for eg AAISP in the UK and any similar ISPs elsewhere, doing > it from home is "impossible". Plusnet seems OK, despite being part of BT, I've not been caught on a blacklist in about four years with them. I believe Zen is OK, also. A&A has an excellent reputation, but rather high prices. > > This is a real shame, as direct to MX smtp delivery can be as secure > as the recipient wants to make it and, more importantly, you actually > know if an email has been delivered. > > One upon a time, many years ago, btinternet were particularly bad > about this, they pretty much never sent a bounce back when an email > was rejected, their forwarders just dropped the email. I've advised three clients not to use BT, and they all ignored me, and they all had email trouble because of it. One was a household-name multinational (small UK subsidiary) who got a BT 'business' account, and was then told that BT didn't offer any email provision and that the staff should all get free Yahoo accounts. I'm not joking. BT still doesn't do email, it was outsourced to Yahoo when it finally started 'providing' email, and then shifted to the Microsoft blob. MS now only allows webmail access or, for an extra price, Outlook to Exchange connection. > > An outbound mailserver does not have to receive email at all, it > doesn't have to accept inbound connections from anywhere and outbound > only needs port 25 (plus things like working DNS) It still needs SPF or DKIM in the DNS records. My server requires that a sender has complementary A and PTR records and that the HELO/EHLO and the MX record contain hostnames which are resolvable in public DNS, and that the sending email address is a valid one. (A very well-known UK restaurant chain sends out order acknowledgements 'from' an invalid address, and it is therefore impossible to tell them they're doing it wrong). So a sender really needs a fixed IP address to be reliable, even if he's not receiving to it. -- Joe
