Definition of no ip directed-broadcast configuration under the interface

Source: Internet
Author: User

About the meaning of no ip directed-broadcast configuration under the interface, we often see a command under the Cisco device interface configuration: no ip directed-broadcast, but many people do not know the meaning of this command, I checked the information and gave a rough explanation. I hope you can understand it. Generally, the Router does not forward the full broadcast package of, but forwards the broadcast package with the host space of 1 by default, for example,, that is to say, when we need to test the host accessibility of a CIDR block, we can ping the broadcast address of the CIDR block. In this way, all IP addresses in the CIDR block will reply to the echo packet to ping the test host. However, if someone wants to maliciously attack this CIDR Block, they can directly use the directed-broadcast feature of the router ip address to launch attacks easily. therefore, for security reasons, we usually configure no ip directed-broadcast on the interface to prevent malicious network attacks. Ip directed-broadcast allows forwarding of broadcast packets with the host bit of all 1. no ip directed-broadcast prohibits forwarding of broadcast packets with the host bit of all 1.

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: 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.