More in detail, would like to know:

what is the default SYN_RECEIVED timer,
how do i get to change it,
are SYN cookies or SYN caches implemented.

I'm about to create a simple special-purpose publically accessible server. i must choose whether using built-in TCP sockets or RAW sockets and re-implement the TCP handshake if these security mechanisms are not present.
What you describe are internals of the TCP stack of the operating system. Python just uses this stack via the socket interface. I doubt that any of these settings can be changed specific to the application at all, i.e. these are system wide settings which can only be changed with administrator privileges.
what anti-ddos security systems python use for socket TCP connections?