Outbound Port 25 Blocking (OP25B)
This page explains about the outbound port 25 blocking, or OP25B.
- ※You will need to change your setting to avoid negative impact from the OP25B implementation.Please refer to information below.
Measures to Prevent Spams
As a step to improve the security of our Internet service and our members, Asahi Net has implemented Outbound Port 25 Blocking (OP25B). This would reduce extensive amount of Spams, or unsolicited bulk email (UBE) as well as virus-infected emails.
What is OP25B?
Outbound Port 25 Blocking (OP25B) is a measure to prevent any intentional or unintentional sending of bulk unsolicited email through an Internet provider's outbound email server. Many of those spams are directly routed using the port 25 to the servers of recipients. By blocking the port 25, it can limit the use of port 25 which accordingly block the flow of spams.
The Merit of Outbound Port 25 Blocking
If your computer is infected with a virus or being hacked by malicious third party, your computer will be taken over and become as a hub for unsolicited bulk email sending in which act can risk your personal identity information.
OP25B prevents such unintentional bulk sending of spams and leakage of your personal information.
Servers Covered by Outbound Port 25 Blocking (OP25B)
Non-Asahi Net outgoing mail server
If you are using a non-Asahi Net outgoing mail server, it is covered by OP25B.
However, if you are assigned a fixed IP address, it will not be covered by OP25B.
- If you wish to continue using a non-Asahi Net outgoing mail server, see the Dealing with OP25B page.
Asahi Net outgoing mail server
- If you are using the Asahi Net outgoing mail server, it is not covered by OP25B.
However, if you are using Asahi Net’s IPv6 connection (IPv4 over IPv6 connection is not included), you are not able to use the Asahi Net outgoing mail server. Email has to be sent through other connection methods.
- If you wish to open Port 25, please set your mailer as recommended by Asahi Net to enhance safety.