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The Japan Email Anti-Abuse Group (JEAG) Drafts Recommendations on the Fight against Spam E-mail <Appendix>

Wireless Sub-working Group Recommendations
The Wireless Sub-working Group examines ways to ensure the flow of wholesome e-mails to mobile phone addresses and enacts countermeasures to prevent spam from being sent to mobile phones.
To realize a flow of wholesome e-mails to mobile phones in this current era of high-speed internet connections, JEAG believes cooperation is necessary on both the outbound side and the inbound side. The sub-working group has thus compiled countermeasures used by ISPs and mobile telecommunication operators that have been proven effective in fighting spam.
The recommended countermeasures are close to being best practices and JEAG would like for companies considering counter-spam measures to use them as a reference when considering their own plan of action.

Outbound Port 25 Blocking Sub-working Group Recommendations
The Outbound Port 25 Blocking Sub-working Group examines ways of implementing Outbound Port 25 Blocking (OP25B), a technology that blocks and removes spam mail directly sent from the dynamic IP addresses of ISPs to mail servers at Outbound Port 25.
The Sub-working Group recommendations include proposals on the implementation process of OP25B and challenges and considerations related to its introduction, as well as proposals for the introduction of Submission Port [1] and SMTP Authorization (SMTP Auth) [2], which should be combined with OP25B implementation.
The number of providers implementing OP25B is increasing, and JEAG hopes to be able to contribute by stopping spam e-mail that originates from Japan as a first step.

Sender Authentication Sub-working Group Recommendations
The Sender Authentication Sub-working Group examines sender authentication technology [3], which is one technological method that makes it possible to determine outbound e-mails of false origin.
With the aim of introducing either SPF [4] as a common IP system or DKIM (DomainKeys) [5] as a common encryption system to pro-actively propagate sender authentication technology, the Sub-working Group's recommendations include proposals for settings and working policies for service.
JEAG expects that spam emails will decrease if more organizations implement sender authentication technology and employ filtering technology based on the results of this authorization technology.

[1]  Submission Port: Item used when sending a mail (called 'Submission'), which JEAG recommends using as Port 587. Standardized by RFC2476.
[2]  SMTP Auth: Technology that confirms a user's identity when a mail is sent and only allows mail to be sent when authorized. Standardized by RFC2554.
[3]  Sender Authentication Technology: A technology that authorizes whether the server of outbound mail origin is appropriate when a user receives a mail.
[4]  SPF: An IP address based sender authentication technology proposed by Meng Wong, a co-founder of in the U.S.
Specifically, permitted sent mail server information is obtained from "envelope" -like sender information (Envelope From), and authorized depending on whether the inbound mail comes from the correct outbound mail server or not.
[5]  DKIM (DomainKeys): A sender authentication technology based on a combination of the electronic signature base technology called DomainKeys advocated by Yahoo! in the U.S. and Identified Internet Mail advocated by Cisco in the U.S.
Specifically, mail is signed on the outbound side when sent by using its own secret key. The inbound side obtains open keys from the DNS (Domain Name Service) server to verify signatures of mails that have been sent.

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