* 황병희: > i did not setup SPF. Instead i think User-Agent/X-Mailer are > important.
The contents of these headers are easily faked, so relying on them is questionable to me. Also, you will encounter User-Agent headers generated by various libraries, like Java SMTP implementations. Finally, what about emails without User-Agent header, which are perfectly valid? SPF, by contrast, has at least some benefit when it comes to spam prevention. -Ralph
