citation needed: SMTP open relay in early RHL?

I use mostly Fedora for laptops, and have for a while. I wrote a
comment on a distribution bug tracker...

https://bugzilla.redhat.com/show_bug.cgi?id=2297635#c7

...saying basically that sysadmins have the same responsibility to
turn off user-tracking features today that we had to turn off
spam-enabling features like open SMTP relays back when those were a
thing.

I recall that early Red Hat Linux had "sendmail" set up as an open
relay, but still looking for a citation for documentation of that.
The LDP tells you how to not run an open relay...

https://tldp.org/HOWTO/Spam-Filtering-for-MX/smtpchecks.html

...and distributions stopped shipping open relays pretty early on.
Anyone recall which if any RHL versions acted as an open relay?

(should have kept better sysadmin notebooks in the 1990s)

-- 
Don Marti <[email protected]>                   
https://blog.zgp.org/