How to defend against spam in Linux

Article Title: how to defend against spam in Linux. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.

I believe that most people who use emails will receive a lot of spam every day. As a network manager, I receive more than hundreds of spam mails every day, so it is imperative to prevent spam.

I. Environment Description

The server of the organization uses RedHat Linux 9.0 and the mail server uses Sendmail 8.12.8. This server is placed on the Intranet and connected to the Internet through a Win2000 Server. The gateway software uses WinRoute Pro 4.2.5.

Ii. Main modification measures

1. Disable the Relay function of Sendmail.

The so-called Relay means that someone else can use this SMTP mail server to send emails to anyone, so that spammers with ulterior motives can use this mail server of the author's organization to send a large number of spam mails, in the end, what others complain about is not the spammers, but the server of the Organization. Therefore, you must disable Open Relay by going to the/etc/mail directory of the Linux server, editing the access file, and removing settings such as "* relay, generally, only "localhost relay" and "127.0.0.1 relay" are available.

Note: After modifying the access file, run makemap hash access. db.

2. Enable SMTP authentication for Sendmail

If the Relay function is disabled, teachers in the organization cannot use software such as OE to send emails? It doesn't matter. You only need to configure the SMTP authentication function for Sendmail, and then enable the SMTP authentication in OE, you can use the SMTP of the unit anywhere.

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