Home > Optional Services > Advanced SPAM Filtering > Service Details

Advanced SPAM Filtering

Service Guide

Rakuten Broadband Premium's "Advanced Spam Filtering Service" just got better! The new and improved SPAM elimination suite now includes the award-winning "Spam Assassin" content filter, a new "GreyList" sender validation system and the highly innovative "SES" (Signed Envelope Sender) NDN authenticity routine.


SES(Signed Envelope Sender)NDN Authenticity Routin

NDN: Non-Delivery Notification. "E-mail that is returned to the sender due to undeliverability."
Non-Delivery Notifications (A.K.A. "bounces" ) that appear in your inbox due to remote mail systems incorrectly interpreting (and returning) undeliverable mail is known as "backscatter". The SES authenticity routine checks all such incoming mails for a GOL-specific "signature" (which is inserted into all outgoing mail sent though the GOL SMTP server) to judge weather the mail actually originated from your account or not. Only E-mail with the presence of the signature confirmed is allowed in.

Blacklist(Part of GOL's Standard Spam Filtering Service)

A comprehensive array of local and real-time lists containing sender addresses, host names, specific words and phrases etc., used to stop well-know spammers, spamming operations, and poorly configured/insecure mail servers.


The Greylist filter is intended as a powerful last wall of defense against cleverly designed SPAM that sneaks by other filters. Incoming mail that seems suspicious is put into a temporary holding queue. Such mail will be stored on the server (24 hours maximum) awaiting confirmation from the sender's remote mail server. If the mail is confirmed legitimate within that time, an entry will be added to the Whitelist (to ensure that all future mail from that sender will be let through unobstructed) and then delivered to your inbox. What this means is that mail that is caught by the Greylist filter may be delayed in reaching your inbox by a few hours but this occurs only once and the sender will not be aware that any delay has occurred.

SPAM Assassin

"Spam Assassin" is a self-learning, self-improving anti-SPAM tool that scans the content (headers and body) of incoming mail for pre-defined "tokens" (certain words, phrases, coding, etc.) that are then assigned a numerical score and added up to be checked against your personal filtering level. Customers have full control over the "strictness" of SPAM Assassin by choosing their own filtering level from a scale of 1 to 20. The score given to each incoming mail by SPAM Assassin can be viewed in the mai's headers. By studying what kind of score is given to the mail you typically receive, a customer can better judge which filtering level is best to suit their needs.


Monthly service: 100 yen/month

* First month's fees are not pro-rated from day of application.
The Advanced SPAM Filtering service becomes available to all mailboxes and aliases attached to the main GOL account at no extra cost.
The filter can be turned on or off as desired for each account attached to the main account. These changes can be easily made at Member's station.


Please proceed to the GOL Member's Station. and following the links to the sign-up page.

Contacting Rakuten Broadband Premium

Any Sales or Technical inquires can be directed to the Customer Center at 0120-987-800, 9.00am-5.30pm, Monday to Friday (excluding National holidays).

Please see here for FAQ.

Terms and Conditions

  1. Rakuten Broadband Premium cannot guarantee 100% protection from SPAM.

  2. Rakuten Broadband Premium will not accept any responsibility for loss of income or data, or damage to hardware or software resulting from an Internet related threat.

All prices shown are excluded tax unless otherwise specified.