Why null0 routes

Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. What is Null 0 interface? Ask Question. Asked 7 years, 7 months ago. Active 4 years, 8 months ago. Viewed 22k times. In which case is ip route Thanks in advance. Improve this question. Mike Pennington Trojan Trojan 1, 5 5 gold badges 16 16 silver badges 29 29 bronze badges.

Add a comment. Active Oldest Votes. Improve this answer. Ryan Foley Ryan Foley 5, 4 4 gold badges 22 22 silver badges 43 43 bronze badges. Null 0 can also be a good alternative to an Access Control List s with the benefit of lower CPU overhead depending on the complexity of requirements. Skip to content. Like this: Like Loading Published by skminhaj. Published December 21, Leave a Reply Cancel reply Enter your comment here Fill in your details below or click an icon to log in:.

Email Address never made public. Follow Following. Sign me up. The Null0 interface provides an optional method for filtering traffic. When a router receives a packet, it searches the ACL. If the action is permit , the router searches the forwarding table and then determines whether to forward or discard the packet.

The Null0 interface must be specified as the outbound interface of unnecessary packets. When a router receives a packet, it searches the forwarding table. If the router finds that the outbound interface of the packet is the Null0 interface, it discards the packet. Using a Null0 interface to filter traffic is more efficient and faster than using an ACL. For example, if you do not want a router to receive packets with a specified destination address, use the Null0 interface for packet filtering.

This only requires a route to be configured.