1 files changed, 177 insertions, 178 deletions

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index bbcc8deda172..a0f6842368c3 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -101,6 +101,11 @@ inet_peer_gc_maxtime - INTEGER
 
 TCP variables: 
 
+somaxconn - INTEGER
+        Limit of socket listen() backlog, known in userspace as SOMAXCONN.
+        Defaults to 128.  See also tcp_max_syn_backlog for additional tuning
+        for TCP sockets.
+
 tcp_abc - INTEGER
         Controls Appropriate Byte Count (ABC) defined in RFC3465.
         ABC is a way of increasing congestion window (cwnd) more slowly
@@ -112,48 +117,51 @@ tcp_abc - INTEGER
                   of two segments to compensate for delayed acknowledgments.
         Default: 0 (off)
 
-tcp_syn_retries - INTEGER
-        Number of times initial SYNs for an active TCP connection attempt
-        will be retransmitted. Should not be higher than 255. Default value
-        is 5, which corresponds to ~180seconds.
+tcp_abort_on_overflow - BOOLEAN
+        If listening service is too slow to accept new connections,
+        reset them. Default state is FALSE. It means that if overflow
+        occurred due to a burst, connection will recover. Enable this
+        option _only_ if you are really sure that listening daemon
+        cannot be tuned to accept connections faster. Enabling this
+        option can harm clients of your server.
 
-tcp_synack_retries - INTEGER
-        Number of times SYNACKs for a passive TCP connection attempt will
-        be retransmitted. Should not be higher than 255. Default value
-        is 5, which corresponds to ~180seconds.
+tcp_adv_win_scale - INTEGER
+        Count buffering overhead as bytes/2^tcp_adv_win_scale
+        (if tcp_adv_win_scale > 0) or bytes-bytes/2^(-tcp_adv_win_scale),
+        if it is <= 0.
+        Default: 2
 
-tcp_keepalive_time - INTEGER
-        How often TCP sends out keepalive messages when keepalive is enabled.
-        Default: 2hours.
+tcp_allowed_congestion_control - STRING
+        Show/set the congestion control choices available to non-privileged
+        processes. The list is a subset of those listed in
+        tcp_available_congestion_control.
+        Default is "reno" and the default setting (tcp_congestion_control).
 
-tcp_keepalive_probes - INTEGER
-        How many keepalive probes TCP sends out, until it decides that the
-        connection is broken. Default value: 9.
+tcp_app_win - INTEGER
+        Reserve max(window/2^tcp_app_win, mss) of window for application
+        buffer. Value 0 is special, it means that nothing is reserved.
+        Default: 31
 
-tcp_keepalive_intvl - INTEGER
-        How frequently the probes are send out. Multiplied by
-        tcp_keepalive_probes it is time to kill not responding connection,
-        after probes started. Default value: 75sec i.e. connection
-        will be aborted after ~11 minutes of retries.
+tcp_available_congestion_control - STRING
+        Shows the available congestion control choices that are registered.
+        More congestion control algorithms may be available as modules,
+        but not loaded.
 
-tcp_retries1 - INTEGER
-        How many times to retry before deciding that something is wrong
-        and it is necessary to report this suspicion to network layer.
-        Minimal RFC value is 3, it is default, which corresponds
-        to ~3sec-8min depending on RTO.
+tcp_congestion_control - STRING
+        Set the congestion control algorithm to be used for new
+        connections. The algorithm "reno" is always available, but
+        additional choices may be available based on kernel configuration.
+        Default is set as part of kernel configuration.
 
-tcp_retries2 - INTEGER
-        How may times to retry before killing alive TCP connection.
-        RFC1122 says that the limit should be longer than 100 sec.
-        It is too small number. Default value 15 corresponds to ~13-30min
-        depending on RTO.
+tcp_dsack - BOOLEAN
+        Allows TCP to send "duplicate" SACKs.
 
-tcp_orphan_retries - INTEGER
-        How may times to retry before killing TCP connection, closed
-        by our side. Default value 7 corresponds to ~50sec-16min
-        depending on RTO. If you machine is loaded WEB server,
-        you should think about lowering this value, such sockets
-        may consume significant resources. Cf. tcp_max_orphans.
+tcp_ecn - BOOLEAN
+        Enable Explicit Congestion Notification in TCP.
+
+tcp_fack - BOOLEAN
+        Enable FACK congestion avoidance and fast retransmission.
+        The value is not used, if tcp_sack is not enabled.
 
 tcp_fin_timeout - INTEGER
         Time to hold socket in state FIN-WAIT-2, if it was closed
@@ -166,24 +174,33 @@ tcp_fin_timeout - INTEGER
         because they eat maximum 1.5K of memory, but they tend
         to live longer. Cf. tcp_max_orphans.
 
-tcp_max_tw_buckets - INTEGER
-        Maximal number of timewait sockets held by system simultaneously.
-        If this number is exceeded time-wait socket is immediately destroyed
-        and warning is printed. This limit exists only to prevent
-        simple DoS attacks, you _must_ not lower the limit artificially,
-        but rather increase it (probably, after increasing installed memory),
-        if network conditions require more than default value.
+tcp_frto - BOOLEAN
+        Enables F-RTO, an enhanced recovery algorithm for TCP retransmission
+        timeouts.  It is particularly beneficial in wireless environments
+        where packet loss is typically due to random radio interference
+        rather than intermediate router congestion.
 
-tcp_tw_recycle - BOOLEAN
-        Enable fast recycling TIME-WAIT sockets. Default value is 0.
-        It should not be changed without advice/request of technical
-        experts.
+tcp_keepalive_time - INTEGER
+        How often TCP sends out keepalive messages when keepalive is enabled.
+        Default: 2hours.
 
-tcp_tw_reuse - BOOLEAN
-        Allow to reuse TIME-WAIT sockets for new connections when it is
-        safe from protocol viewpoint. Default value is 0.
-        It should not be changed without advice/request of technical
-        experts.
+tcp_keepalive_probes - INTEGER
+        How many keepalive probes TCP sends out, until it decides that the
+        connection is broken. Default value: 9.
+
+tcp_keepalive_intvl - INTEGER
+        How frequently the probes are send out. Multiplied by
+        tcp_keepalive_probes it is time to kill not responding connection,
+        after probes started. Default value: 75sec i.e. connection
+        will be aborted after ~11 minutes of retries.
+
+tcp_low_latency - BOOLEAN
+        If set, the TCP stack makes decisions that prefer lower
+        latency as opposed to higher throughput.  By default, this
+        option is not set meaning that higher throughput is preferred.
+        An example of an application where this default should be
+        changed would be a Beowulf compute cluster.
+        Default: 0
 
 tcp_max_orphans - INTEGER
         Maximal number of TCP sockets not attached to any user file handle,
@@ -197,41 +214,6 @@ tcp_max_orphans - INTEGER
         more aggressively. Let me to remind again: each orphan eats
         up to ~64K of unswappable memory.
 
-tcp_abort_on_overflow - BOOLEAN
-        If listening service is too slow to accept new connections,
-        reset them. Default state is FALSE. It means that if overflow
-        occurred due to a burst, connection will recover. Enable this
-        option _only_ if you are really sure that listening daemon
-        cannot be tuned to accept connections faster. Enabling this
-        option can harm clients of your server.
-
-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'
-        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
-        in your logs, but investigation shows that they occur
-        because of overload with legal connections, you should tune
-        another parameters until this warning disappear.
-        See: tcp_max_syn_backlog, tcp_synack_retries, tcp_abort_on_overflow.
-
-        syncookies seriously violate TCP protocol, do not allow
-        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
-        is seriously misconfigured.
-
-tcp_stdurg - BOOLEAN
-        Use the Host requirements interpretation of the TCP urg 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_max_syn_backlog - INTEGER
         Maximal number of remembered connection requests, which are
         still did not receive an acknowledgment from connecting client.
@@ -239,24 +221,34 @@ tcp_max_syn_backlog - INTEGER
         and 128 for low memory machines. If server suffers of overload,
         try to increase this number.
 
-tcp_window_scaling - BOOLEAN
-        Enable window scaling as defined in RFC1323.
+tcp_max_tw_buckets - INTEGER
+        Maximal number of timewait sockets held by system simultaneously.
+        If this number is exceeded time-wait socket is immediately destroyed
+        and warning is printed. This limit exists only to prevent
+        simple DoS attacks, you _must_ not lower the limit artificially,
+        but rather increase it (probably, after increasing installed memory),
+        if network conditions require more than default value.
 
-tcp_timestamps - BOOLEAN
-        Enable timestamps as defined in RFC1323.
+tcp_mem - vector of 3 INTEGERs: min, pressure, max
+        min: below this number of pages TCP is not bothered about its
+        memory appetite.
 
-tcp_sack - BOOLEAN
-        Enable select acknowledgments (SACKS).
+        pressure: when amount of memory allocated by TCP exceeds this number
+        of pages, TCP moderates its memory consumption and enters memory
+        pressure mode, which is exited when memory consumption falls
+        under "min".
 
-tcp_fack - BOOLEAN
-        Enable FACK congestion avoidance and fast retransmission.
-        The value is not used, if tcp_sack is not enabled.
+        max: number of pages allowed for queueing by all TCP sockets.
 
-tcp_dsack - BOOLEAN
-        Allows TCP to send "duplicate" SACKs.
+        Defaults are calculated at boot time from amount of available
+        memory.
 
-tcp_ecn - BOOLEAN
-        Enable Explicit Congestion Notification in TCP.
+tcp_orphan_retries - INTEGER
+        How may times to retry before killing TCP connection, closed
+        by our side. Default value 7 corresponds to ~50sec-16min
+        depending on RTO. If you machine is loaded WEB server,
+        you should think about lowering this value, such sockets
+        may consume significant resources. Cf. tcp_max_orphans.
 
 tcp_reordering - INTEGER
         Maximal reordering of packets in a TCP stream.
@@ -267,20 +259,23 @@ tcp_retrans_collapse - BOOLEAN
         On retransmit try to send bigger packets to work around bugs in
         certain TCP stacks.
 
-tcp_wmem - vector of 3 INTEGERs: min, default, max
-        min: Amount of memory reserved for send buffers for TCP socket.
-        Each TCP socket has rights to use it due to fact of its birth.
-        Default: 4K
+tcp_retries1 - INTEGER
+        How many times to retry before deciding that something is wrong
+        and it is necessary to report this suspicion to network layer.
+        Minimal RFC value is 3, it is default, which corresponds
+        to ~3sec-8min depending on RTO.
 
-        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: 16K
+tcp_retries2 - INTEGER
+        How may times to retry before killing alive TCP connection.
+        RFC1122 says that the limit should be longer than 100 sec.
+        It is too small number. Default value 15 corresponds to ~13-30min
+        depending on RTO.
 
-        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
+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
 
 tcp_rmem - vector of 3 INTEGERs: min, default, max
         min: Minimal size of receive buffer used by TCP sockets.
@@ -299,79 +294,91 @@ tcp_rmem - vector of 3 INTEGERs: min, default, max
         net.core.rmem_max, "static" selection via SO_RCVBUF does not use this.
         Default: 87380*2 bytes.
 
-tcp_mem - vector of 3 INTEGERs: min, pressure, max
-        min: below this number of pages TCP is not bothered about its
-        memory appetite.
+tcp_sack - BOOLEAN
+        Enable select acknowledgments (SACKS).
 
-        pressure: when amount of memory allocated by TCP exceeds this number
-        of pages, TCP moderates its memory consumption and enters memory
-        pressure mode, which is exited when memory consumption falls
-        under "min".
+tcp_slow_start_after_idle - BOOLEAN
+        If set, provide RFC2861 behavior and time out the congestion
+        window after an idle period.  An idle period is defined at
+        the current RTO.  If unset, the congestion window will not
+        be timed out after an idle period.
+        Default: 1
 
-        max: number of pages allowed for queueing by all TCP sockets.
+tcp_stdurg - BOOLEAN
+        Use the Host requirements interpretation of the TCP urg pointer field.
+        Most hosts use the older BSD interpretation, so if you turn this on
+        Linux might not communicate correctly with them.
+        Default: FALSE
 
-        Defaults are calculated at boot time from amount of available
-        memory.
+tcp_synack_retries - INTEGER
+        Number of times SYNACKs for a passive TCP connection attempt will
+        be retransmitted. Should not be higher than 255. Default value
+        is 5, which corresponds to ~180seconds.
 
-tcp_app_win - INTEGER
-        Reserve max(window/2^tcp_app_win, mss) of window for application
-        buffer. Value 0 is special, it means that nothing is reserved.
-        Default: 31
+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'
+        Default: FALSE
 
-tcp_adv_win_scale - INTEGER
-        Count buffering overhead as bytes/2^tcp_adv_win_scale
-        (if tcp_adv_win_scale > 0) or bytes-bytes/2^(-tcp_adv_win_scale),
-        if it is <= 0.
-        Default: 2
+        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
+        in your logs, but investigation shows that they occur
+        because of overload with legal connections, you should tune
+        another parameters until this warning disappear.
+        See: tcp_max_syn_backlog, tcp_synack_retries, tcp_abort_on_overflow.
 
-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
+        syncookies seriously violate TCP protocol, do not allow
+        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
+        is seriously misconfigured.
 
-tcp_low_latency - BOOLEAN
-        If set, the TCP stack makes decisions that prefer lower
-        latency as opposed to higher throughput.  By default, this
-        option is not set meaning that higher throughput is preferred.
-        An example of an application where this default should be
-        changed would be a Beowulf compute cluster.
-        Default: 0
+tcp_syn_retries - INTEGER
+        Number of times initial SYNs for an active TCP connection attempt
+        will be retransmitted. Should not be higher than 255. Default value
+        is 5, which corresponds to ~180seconds.
+
+tcp_timestamps - BOOLEAN
+        Enable timestamps as defined in RFC1323.
 
 tcp_tso_win_divisor - INTEGER
-       This allows control over what percentage of the congestion window
-       can be consumed by a single TSO frame.
-       The setting of this parameter is a choice between burstiness and
-       building larger TSO frames.
-       Default: 3
+        This allows control over what percentage of the congestion window
+        can be consumed by a single TSO frame.
+        The setting of this parameter is a choice between burstiness and
+        building larger TSO frames.
+        Default: 3
 
-tcp_frto - BOOLEAN
-        Enables F-RTO, an enhanced recovery algorithm for TCP retransmission
-        timeouts.  It is particularly beneficial in wireless environments
-        where packet loss is typically due to random radio interference
-        rather than intermediate router congestion.
+tcp_tw_recycle - BOOLEAN
+        Enable fast recycling TIME-WAIT sockets. Default value is 0.
+        It should not be changed without advice/request of technical
+        experts.
 
-tcp_allowed_congestion_control - STRING
-        Show/set the congestion control choices available to non-privileged
-        processes. The list is a subset of those listed in
-        tcp_available_congestion_control.
-        Default is "reno" and the default setting (tcp_congestion_control).
+tcp_tw_reuse - BOOLEAN
+        Allow to reuse TIME-WAIT sockets for new connections when it is
+        safe from protocol viewpoint. Default value is 0.
+        It should not be changed without advice/request of technical
+        experts.
 
-tcp_available_congestion_control - STRING
-        Shows the available congestion control choices that are registered.
-        More congestion control algorithms may be available as modules,
-        but not loaded.
+tcp_window_scaling - BOOLEAN
+        Enable window scaling as defined in RFC1323.
 
-tcp_congestion_control - STRING
-        Set the congestion control algorithm to be used for new
-        connections. The algorithm "reno" is always available, but
-        additional choices may be available based on kernel configuration.
-        Default is set as part of kernel configuration.
+tcp_wmem - vector of 3 INTEGERs: min, default, max
+        min: Amount of memory reserved for send buffers for TCP socket.
+        Each TCP socket has rights to use it due to fact of its birth.
+        Default: 4K
 
-somaxconn - INTEGER
-        Limit of socket listen() backlog, known in userspace as SOMAXCONN.
-        Defaults to 128.  See also tcp_max_syn_backlog for additional tuning
-        for TCP sockets.
+        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: 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
 
 tcp_workaround_signed_windows - BOOLEAN
         If set, assume no receipt of a window scaling option means the
@@ -380,13 +387,6 @@ tcp_workaround_signed_windows - BOOLEAN
         not receive a window scaling option from them.
         Default: 0
 
-tcp_slow_start_after_idle - BOOLEAN
-        If set, provide RFC2861 behavior and time out the congestion
-        window after an idle period.  An idle period is defined at
-        the current RTO.  If unset, the congestion window will not
-        be timed out after an idle period.
-        Default: 1
-
 CIPSOv4 Variables:
 
 cipso_cache_enable - BOOLEAN
@@ -986,4 +986,3 @@ no_cong_thresh FIXME
 slot_timeout FIXME
 warn_noreply_time FIXME
 
-$Id: ip-sysctl.txt,v 1.20 2001/12/13 09:00:18 davem Exp $