Press Releases 2006

SOFTBANK Group to take stronger anti-spam measures on its Internet services through phased introduction of “Outbound Port25 Blocking”

Apr. 3, 2006

The SOFTBANK Group (SOFTBANK BB Corp., BB TECHNOLOGY Corp., JAPAN TELECOM CO., LTD., Yahoo Japan Corporation, SOFTBANK IDC Corp., “the Group”) decided to take tougher action to prevent spam on the Internet services offered by each Group companies by beginning, in June of this year, the phased introduction of “Outbound Port25 Blocking* (hereinafter “OP25B”)”, a technology that restricts sending spam.

Spam these days often involves not only deliberate transmission but also unwitting ordinary users’ sending email without being aware their PC is infected by viruses etc., which has become a major social issues. The Group has been examining anti-spam technology by, for example, participating in the activities of the Japan Email Anti-Abuse Group (“JEAG”,, a working group that promotes anti-spam initiatives. The introduction of OP25B is part of such efforts.

OP25B is a technology that restricts spam sent directly from an Internet user’s connection to the recipient’s email server. By implementing this measure, the Group will be able to restrict outgoing spam and significantly reduce the amount of spam that is sent using the Group’s services.

The Group will continue its active efforts to fight against spam in corporation with JEAG and other parties, in order to give users a safe and trouble-free email service.

Services covered by OP25B

Service name Service provider
Yahoo Japan Corporation
SoftBank Broadband Service
(Enjoy BB, Nexyz.BB)
JENS SpinNet
ULTINA Internet
BB Mobile Point
  • *“Outbound Port25 Blocking” is technical measures aimed at restricting sending spam directly to the recipient’s email server, instead of passing through the outgoing email server of Internet providers. Generally, email is sent using port 25 of TCP/IP, and because this solution partially “blocks” the use of port 25, it is known as “Outbound Port 25Blocking (OP25B).” In Japan, JEAG ( is playing a leading role in undertaking technical studies of OP25B.
  • *Details of OP25B implementation on each service will be announced in phases by the service providers concerned.
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