How to set source address when sending using and UDP socket

Question

I\'ve two pc using VRRP for redundancy. So every PC (Linux) has a physical and a Virtual IP address.

I\'ve a software (C++) with a client/server architecture with UD

Answer 1

When the kernel needs to send something through a socket it performs these steps

• if the socket is bound, use that source address
• is the socket is not bound, it looks around for interfaces and selects a source address

So you need to bind(2) your socket to your desired address. For more information: Source Address Selection.