Networking Improvements Utilizing Kernel Settings

This implements networking security improvements by tweaking kernel settings. This is done via the sysctl interface in Linux. The security improvements are selectively significant: If they have no trade-off in most situations they are fine; if they have a quantifiable trade-off but it is sufficiently minimal and they are sufficiently justifiable they are fine; if they have a quantifiable trade-off and only lessen an attack or otherwise do not significantly improve security they are not used.