From kernel doc:
tcp_rfc1337 - BOOLEAN If set, the TCP stack behaves conforming to RFC1337. If unset, we are not conforming to RFC, but prevent TCP TIME_WAIT assassination. Default: 0
- With setting
0the system would 'assassinate' a socket in time_wait prematurely upon receiving a RST. While this might sound like a good idea (it frees up a socket quicker), it opens the door for tcp sequence problems/syn replay. Those problems were described in RFC1337 and enabling the setting
1is one way to deal with them (letting TIME_WAIT packets idle out even if a reset is received, so that the sequence number cannot be reused meanwhile). The wiki is correct in my view.
Kernel doc is wrong here - "prevent" should read "enable".--Indigo (talk) 21:12, 17 September 2013 (UTC)
The official documentation states that these two variables "Contain[s], as a percentage of total available memory that contains free pages and reclaimable pages,..." and that "The total available memory is not equal to total system memory.". However the comment underneath talks about them as if they were a percentage of system memory, making it quite confusing, e.g. I have 6GiB of system memory but only 1-2GiB available.
Also the defaults seem to have changed, I have