Email error 2

I don't think anyone said they would solve *all* email problems

is it because it doesn't match, or is it because it includes giveaways like "dsl" or "home" or "dynamic" in the rDNS?

Either way, amazed you didn't run into that at least a decade ago ... not all ISPs are so mean that they won't do custom rDNS for static subnets (e.g. plusnet do).

It's up to the whim of the mail server admin. I could do that if I wanted, but it's stupid. No medium-to-large business ever sends mail 'from' its own domain. That's daft as well, because it makes it harder to see if the mail is genuine, but it's the way things are done. It's all outsourced, and any large business is likely to send mail from a different IP address than its MX resolves to. Often two different companies are involved, one for sending mail and another providing anti-spam services for received mail.

I require the sender to have:

-complementary A/PTR records, the hostname not necessarily bearing any relationship to the Reply-To email address, therefore not the same as the domain MX record.

-HELO/EHLO to be a hostname resolvable in public DNS, again not necessarily related to the Reply-To domain.

-HELO/EHLO hostname *not* to be on my own domain, nor my IP address, it's surprising how many spammers do this.

That's enough to discourage most bots, and I also require either a response to an ident request (port 113) or not to drop the connection for 30 seconds if it can't do that. That gets the rest of the bots, as nobody runs an ident server these days and bots won't wait for 30 seconds, but a proper SMTP server will.

Anything more restrictive than that is counter-productive. I send mail for currently three domains, and while the PTR specification does allow for multiple records, I doubt that any software will handle more than one.

MS wants everyone in the world to use Outlook or webmail. So far, I haven't run into this problem, probably because nobody I currently send to is outsourcing to MS. BT does.

Uno were my ISP prior to FTTP availability and they did allow custom DNS. For a little over a year MS didn't reject connections, it's only in the last 2 months that it's happened.

Malcolm

No. there are good reasons for that.

Set up your own relay on a VPS. They WILL allow the address to be mapped to your domain

'Fraid that isn't the case: delivery to the SMTP target of big mailers like gmail doesn't mean it got to the recipient at all.

Will get kicked around anti-spam and other multiple servers before it

That's up to them is they want to redirect incoming mail via other servers. But isn't it considered in law to have been delivered if accepted by the registered mailserver? Reading has nothing to do with it, it's their choice not to open something which has been delivered to them?

Malcolm

For ages I have enabled this Postfix option

reject_unknown_client_hostname (with Postfix < 2.3: reject_unknown_client) Reject the request when 1) the client IP address->name mapping fails, or 2) the name->address mapping fails, or 3) the name->address mapping does not match the client IP address.

See this archive of my web site from 2007

For my domain the reverse and forward lookups loop: $ dig +short -x 82.68.155.94 wylie.me.uk. $ dig +short wylie.me.uk

Is your problem that yours don't?

$ dig +short loades.net

My ISP, Zen, allows me to configure the reverse DNS lookup.

I have my own domain and send and receive via my domain host (relayed via my home server, but our PCs/mobile phones could go direct to our domain host's servers). So my ISP has nothing to do with my email at all. If I change ISPs, the only change for my email is the general update of my domain records with my new static IP address.

So far, I am on my 4th ISP, without change to my email setup.

Same here, although I've been with the same ISP for nearly 23 years!

I also run my own DNS for all my domains, and so I keep SPF/DKIM/DMARC up to date myself.

I know of no such law.

I often get mail delivered out of sequence and it shows up as being held in internal mail systems for sometimes hours, additionally I know from experience that I have dumped an email into gmails MX server and not seen it received in the destination mailbox for many minutes.

An email I sent to a defendant against whom I was claiming in the County Court denied receiving my emails as his defence. I produced the SMTP log which showed acceptance by the defendant's mailserver of the emails, the Judge accepted that the emails had been delivered to the defendant and awarded Judgement in my favour.

Malcolm

That is not a law, that is a fairly shaky legal precedent. weak circumstantial evidence.

About as unassailable as a picture of a parcel on your doorstep that the drivers mate comes along and removes 3 seconds later.

How did you get hold of that log?

Would be on his sending machine - presumably a linux local relay. Or a linux desktop

Does his not imply he's getting the log either from a mail server he's running, or that he's got it from the destination user's mail server?

Yes, but there would be no point in forging it as the destination log will have a matching entry which he cannot tamper with, and the owner of that log would have no interest in also forging the entry.

As it's a legal case, I would expect him to have requested the destination log, and as long as the owner wasn't a rogue operator like Yahoo or Google, they could be expected to oblige.

No.

You cab see in your own logs that the mail transaction completed OK. And the remote machine said 'OK. I got it'

Doesn't guarantee the far end has read it mind you

OK. I was just interested in the process.

Sure, but he could forge his own log. And if the other party (and the judge) were competely non-technical (and would thus not think of getting hold of the corresponding other-end's log), he might get away with it.

This is also true.