Unauthorized use of Sendmail security

Source: Internet
Author: User

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!

  • SMTP greetings for Sendmail security
  • Sendmail security:/etc/aliases file
  • Smrsh for Sendmail security
  • How to Set a virtual domain in Sendmail
  • Introduction to Sendmail
  • Illustration: Sendmail Working Environment
  • How to install the Sendmail server in Linux

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.