“Email is not intended for file transfer!” In all seriousness, I set mine at 10MB, any higher and you might get rejections from remote SMTP servers. If your company/client does use a lot of larger files, I might be convinced to set it at 15 or 20MB but no higher than that. I instruct clients … Read more
Reverse DNS can only really have one name — if you list more than one, DNS will just round-robin between them. So you just have to pick one “official” name for the server and always use that. All the other domains are, in essence, just aliases to the original. Most services don’t care what the … Read more
Take a look at this collection of example IMAP server sessions. Essentially whenever you see PERMANENTFLAGS contain \*, the server will support user-defined flags. To add to that list, here is an excerpt from a Gimap (Google Mail IMAP) session: * OK Gimap ready for requests from 192.0.2.1 5if380490pzk.17 a login username password * CAPABILITY … Read more
I can vouch for #2 (reverse PTR) being important, but not #4 (mail server domain matching “from”). We set up mail servers all the time, and most mail hosts don’t really even care about #2. The main thorn is always AOL, and they list standards you can check off.