Editing Anti-spam techniques (section)

===Port 25 interception===
[[Network address translation]] can be used to intercept all port 25 (SMTP) traffic and direct it to a mail server that enforces rate limiting and egress spam filtering.  This is commonly done in hotels,<ref>[http://ask-leo.com/why_cant_i_send_mail_from_my_hotel_room.html Why can't I send mail from my hotel room?] {{webarchive|url=https://web.archive.org/web/20060110041305/http://ask-leo.com/why_cant_i_send_mail_from_my_hotel_room.html |date=2006-01-10 }} AskLeo!, December 2005</ref> but it can cause [[email privacy]] problems, as well making it impossible to use [[Simple Mail Transfer Protocol#STARTTLS or "Opportunistic TLS"|STARTTLS]] and [[SMTP-AUTH]] if the port 587 submission port isn't used.