How can I get the interface name/index associated with a TCP socket?

Question

I\'m writing a TCP server that needs to know which interface each connection arrived from. I cannot use the address/subnet to deduce which interface was used, since there mi

Answer 1

Obviously not something I've looked into very deeply, let alone tried, this might be one for the "so crazy it just might work" basket...

If it's really only ever going to be for Linux, you could write a custom netfilter module which tracks the incoming connections and notes which interface they come in on, and writes that information somewhere for your server application to read.