Unauthorized use of Sendmail security

SendmailIt is the most important Email transmission proxy program. Once someone else abused it illegally, it will cause unnecessary consequences. I will introduce you to a solution!

The latest version of Sendmail (8.9.3) adds a strong anti-spoofing feature. They can prevent unauthorized users from abusing your email server. Edit your "/etc/sendmail. cf" file and modify this configuration file so that your email server can block spoofing emails.

Edit the "sendmail. cf" file (vi/etc/sendmail. cf) and change the following line:

O PrivacyOptions = authwarnings

Changed:

O PrivacyOptions = authwarnings, noexpn, novrfy

Set "noexpn" to enable sendmail to disable all SMTP "EXPN" commands, which also causes sendmail to reject all SMTP "VERB" commands. Set "novrfy" to enable sendmail to disable all SMTP "VRFY" commands. Such changes can prevent attackers from using the "EXPN" and "VRFY" commands, which are abused by those who are not regular.

After reading this article, do you think it is very easy to improve the security of your Sendmail server! Hope you can help me!

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