`smtpd.SMTPServer` takes argument `remoteaddr`, however this is only used in subclass `smtpd.DebuggingServer`.

Would anyone object to a patch which removes `remoteaddr` from `smtpd.SMTPServer.__init__` and places it into `smtpd.DebuggingServer.__init__` instead?

Naturally this would be backwards incompatible

We won't make such a backward-incompatible change. Because subclassing is how you extend SMTPServer, it's likely to be used by other derived classes, not in the standard library.

I could see some argument for making it optional and default to None, but that's about the extent of what I would support.

PS: It's used in PureProxy, not DebuggingServer (at least in 3.6, where I checked).

Apologies for the typo, it is indeed `PureProxy`. Setting a default of `None` sounds like a good plan, since it won't break backwards compatibility.

Tangentially, I'm kind of hoping we can get this into 3.6 as an asyncio replacement for smtpd: https://gitlab.com/python-smtpd-hackers/aiosmtpd

I'd forgotten that issue 25008 is about deprecating SMTPServer (or not, there are multiple opinions on it).

I'm closing this as won't fix simce smtpd.py is deprecated and likely won't see any future improvements.  Please take a look at aiosmtpd as a much better third party replacement.