Let a ping pass through an other interface on Redhat/CentOS 7/8
Wanted alive or dead : Ping
![Let a ping pass through an other interface on Redhat/CentOS 7/8](/content/images/size/w2000/2022/07/hi-tech-technology-wi-fi.jpg)
![](https://makz.me/content/images/2022/07/dia.png)
In this example, the client send a ping to 172.25.100.2 (the interface B of the server through interface A).
By default Redhat/CentOS 7 don't respond to a ping coming from an other interface than the one who is asked, no reply is returned from the server
A TCPdump can show you the server receive the request but do not send a single reply.
The solution is simple.
echo 2 > /proc/sys/net/ipv4/conf/all/rp_filter