but not loaded.
tcp_base_mss - INTEGER
- The initial value of search_low to be used by Packetization Layer
- Path MTU Discovery (MTU probing). If MTU probing is enabled,
- this is the inital MSS used by the connection.
+ The initial value of search_low to be used by the packetization layer
+ Path MTU discovery (MTU probing). If MTU probing is enabled,
+ this is the initial MSS used by the connection.
tcp_congestion_control - STRING
Set the congestion control algorithm to be used for new
timeouts. It is particularly beneficial in wireless environments
where packet loss is typically due to random radio interference
rather than intermediate router congestion. F-RTO is sender-side
- only modification. Therefore it does not require any support from
- the peer, but in a typical case, however, where wireless link is
- the local access link and most of the data flows downlink, the
- faraway servers should have F-RTO enabled to take advantage of it.
+ only modification. Therefore it does not require any support from
+ the peer.
+
If set to 1, basic version is enabled. 2 enables SACK enhanced
F-RTO if flow uses SACK. The basic version can be used also when
SACK is in use though scenario(s) with it exists where F-RTO
memory.
tcp_moderate_rcvbuf - BOOLEAN
- If set, TCP performs receive buffer autotuning, attempting to
+ If set, TCP performs receive buffer auto-tuning, attempting to
automatically size the buffer (no greater than tcp_rmem[2]) to
match the size required by the path for full throughput. Enabled by
default.
pressure.
Default: 8K
- default: default size of receive buffer used by TCP sockets.
+ default: initial size of receive buffer used by TCP sockets.
This value overrides net.core.rmem_default used by other protocols.
Default: 87380 bytes. This value results in window of 65535 with
default setting of tcp_adv_win_scale and tcp_app_win:0 and a bit
max: maximal size of receive buffer allowed for automatically
selected receiver buffers for TCP socket. This value does not override
- net.core.rmem_max, "static" selection via SO_RCVBUF does not use this.
- Default: 87380*2 bytes.
+ net.core.rmem_max. Calling setsockopt() with SO_RCVBUF disables
+ automatic tuning of that socket's receive buffer size, in which
+ case this value is ignored.
+ Default: between 87380B and 4MB, depending on RAM size.
tcp_sack - BOOLEAN
Enable select acknowledgments (SACKS).
Default: 1
tcp_stdurg - BOOLEAN
- Use the Host requirements interpretation of the TCP urg pointer field.
+ Use the Host requirements interpretation of the TCP urgent pointer field.
Most hosts use the older BSD interpretation, so if you turn this on
Linux might not communicate correctly with them.
Default: FALSE
tcp_syncookies - BOOLEAN
Only valid when the kernel was compiled with CONFIG_SYNCOOKIES
Send out syncookies when the syn backlog queue of a socket
- overflows. This is to prevent against the common 'syn flood attack'
+ overflows. This is to prevent against the common 'SYN flood attack'
Default: FALSE
Note, that syncookies is fallback facility.
It MUST NOT be used to help highly loaded servers to stand
- against legal connection rate. If you see synflood warnings
+ against legal connection rate. If you see SYN flood warnings
in your logs, but investigation shows that they occur
because of overload with legal connections, you should tune
another parameters until this warning disappear.
to use TCP extensions, can result in serious degradation
of some services (f.e. SMTP relaying), visible not by you,
but your clients and relays, contacting you. While you see
- synflood warnings in logs not being really flooded, your server
+ SYN flood warnings in logs not being really flooded, your server
is seriously misconfigured.
tcp_syn_retries - INTEGER
Enable window scaling as defined in RFC1323.
tcp_wmem - vector of 3 INTEGERs: min, default, max
- min: Amount of memory reserved for send buffers for TCP socket.
+ min: Amount of memory reserved for send buffers for TCP sockets.
Each TCP socket has rights to use it due to fact of its birth.
Default: 4K
- default: Amount of memory allowed for send buffers for TCP socket
- by default. This value overrides net.core.wmem_default used
- by other protocols, it is usually lower than net.core.wmem_default.
+ default: initial size of send buffer used by TCP sockets. This
+ value overrides net.core.wmem_default used by other protocols.
+ It is usually lower than net.core.wmem_default.
Default: 16K
- max: Maximal amount of memory allowed for automatically selected
- send buffers for TCP socket. This value does not override
- net.core.wmem_max, "static" selection via SO_SNDBUF does not use this.
- Default: 128K
+ max: Maximal amount of memory allowed for automatically tuned
+ send buffers for TCP sockets. This value does not override
+ net.core.wmem_max. Calling setsockopt() with SO_SNDBUF disables
+ automatic tuning of that socket's send buffer size, in which case
+ this value is ignored.
+ Default: between 64K and 4MB, depending on RAM size.
tcp_workaround_signed_windows - BOOLEAN
If set, assume no receipt of a window scaling option means the
UNDOCUMENTED:
-dev_weight FIXME
-discovery_slots FIXME
-discovery_timeout FIXME
-fast_poll_increase FIXME
-ip6_queue_maxlen FIXME
-lap_keepalive_time FIXME
-lo_cong FIXME
-max_baud_rate FIXME
-max_dgram_qlen FIXME
-max_noreply_time FIXME
-max_tx_data_size FIXME
-max_tx_window FIXME
-min_tx_turn_time FIXME
-mod_cong FIXME
-no_cong FIXME
-no_cong_thresh FIXME
-slot_timeout FIXME
-warn_noreply_time FIXME
-
+/proc/sys/net/core/*
+ dev_weight FIXME
+
+/proc/sys/net/unix/*
+ max_dgram_qlen FIXME
+
+/proc/sys/net/irda/*
+ fast_poll_increase FIXME
+ warn_noreply_time FIXME
+ discovery_slots FIXME
+ slot_timeout FIXME
+ max_baud_rate FIXME
+ discovery_timeout FIXME
+ lap_keepalive_time FIXME
+ max_noreply_time FIXME
+ max_tx_data_size FIXME
+ max_tx_window FIXME
+ min_tx_turn_time FIXME