May  18, 2006
SpinNet Customer Support Center
 
Outbound Port25 Blocking
 
Blocking SPAM!What is Outbound Port25 Blocking?

Nowadays, sending methods used to send junk mail, such as virus mail or Phishing mail, directly to other mail servers without using the mail server of the provider that the user employs for the Internet connection are becoming serious security problems.
To block junk mail to be sent using the method mentioned above, Outbound Port25 Blocking is used to prohibit access to an outgoing mail server other than the mail server of the provider that the user employs for the Internet connection.
Outbound Port25 Blocking is also called "OP25B" for short, and Internet providers in Japan start using this function as a mechanism to block junk mail. The following images illustrate Outbound Port25 Blocking when SpinNet starts using it.

 
How SPAM is blocked
 
Effect of Outbound Port25 Blocking implementation
Useful to prevent unconscious mass-mailing and accidental personal information leakage!
An unauthorized access to your computer or virus infection may cause accidental mass-mailing to other mail servers or classified information leaking from your computer. However, junk mail sending can be reduced by blocking port25.
 
 Implementation of Outbound Port25 Blocking
  • June 2006
    Restriction on outgoing mail for mobile phones

    Prohibit direct sending to a mobile phone mail server without using SpinNet mail server.

  • October 2006
    Restriction on mail sent to an outgoing mail server other than SpinNet mail server

    Prohibit all mail to be sent without using SpinNet mail server. However, mail can be sent by setting your e-mail software when an outgoing mail server other than SpinNet mail server provides Submission Port587.
 
Customer to be affected
Among the users of SpinNet eADSL service, FLET'S ADSL, FLET'S ISDN, B FLET'S, and FLET'S HIKARI Premium, customers using an outgoing mail server other than SpinNet mail server.
 
 
Providing Submission Port 587
 
About Submission Port587 and POP before SMTP
We provide Submission Port587 for customers who are using an Internet connection of a provider who implements Outbound Port25 Blocking.
Conventionally, port25 is typically used, however, "Submission Port" is a "sending-only destination port" used to send e-mail messages from your e-mail software other than using port25. Mail servers of providers where Outbound Port25 Blocking is implemented restrict mail to be sent through port25. To solve this problem, providers provide a new communication route, port587, called "Submission Port587" instead of the port25 communication route.
 
Customers to be affected
For a customer who is using an Internet connection of a provider implementing Outbound Port25 Blocking, mail can be sent by changing your settings to Submission Port587.

※No need to change for users who are using SpinNet connection.
 
How to change the settings
Please set Submission Port587 according to the following page.
Please refer to this page for Submission Port587 setting.
 
Q&A
Please refer to this page if you have any questions about Outbound Port25 Blocking.


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