>     On 24/09/2020 13:43, Jim Jackson wrote:

> >       Mostly. Somemail servers do a reverse IP lookup and see if it
> > matches your envelope From domain. 

>     Yes, this is an annoyance. There are two ways round this: (1)
>       Change your server's SMTP From domain to be the same as your
>       static IP's PTR hostname, and (2) ask your ISP to change the
>       reverse DNS to be the name of your mail server.
>     Option 1 is a bit embarrassing if anyone notices (e.g.
>       "host-46462.static.bugtown.myisp.net" isn't too cool as the
> name
>       of your mail server) but I don't see any technical downside,
>       although DMARC might perhaps be an issue nowadays.
>     I can confirm that I done option 2 in the past to good effect (on
>       Eclipse Internet in case anyone cares) but I've not tried to do
> it
>       more recently. I suspect that some ISPs might be a bit choosy
>       about this nowadays just in case you're a spammer.