They pass some values to the linux kernel, through the proc filesystem. These are either boolean values ( 0 or 1) used to define whether a particular feature is enabled or disabled, or integer values used to define various things (i.e. the size of some buffers in bytes, the time units after which idle connection sessions will be killed or the local port range for establishing outgoing connections). I suggest you don't change any of them unless you have a specific reason, since the optimum values vary greatly from application to application and the defaults are sensible in most cases.
You should be able to find detailed information if you query each element's name in google (i.e. "/proc/sys/net/ipv4/ip_forward"), some of them are easy to explain in one line, however some others are quite a bit more complicated. In general, options under /proc/sys/net/ipv4 define the behaviour of the tcp/ip stack (things like connection timeouts, available port range for initiating outgoing connections, activation of technical infrastructures like syn cookies -used against DDoS- or routing), options under /proc/sys/fs define the behaviour of filesystem drivers (things like max number of files to allow simultaneous access to), options under /proc/sys/vm the management of the virtual memory system and the elements under /proc/sys/net/core, lower level networking options.
There are many many more, most of which are documented in the linux kernel documentation, if you are curious try exploring the various kernel components through the menuconfig interface ("make menuconfig" in the path where you extracted linux kernel source, and press "?" for a description and a reference to more detailed info -if there is one)
PS. Notice that /proc is not a physical filesystem, it exists only in memory, so any of these changes must be re-written upon reboot.
Re: this is regarding the connectio
12 years 6 months ago #12844