X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;ds=sidebyside;f=Documentation%2Fnetworking%2Fip-sysctl.txt;fp=Documentation%2Fnetworking%2Fip-sysctl.txt;h=f12007b80a466e33fad7efb03dfe7e4f20913462;hb=43bc926fffd92024b46cafaf7350d669ba9ca884;hp=a2c893a7475d799ec0fd7c32a891f48141a6029a;hpb=cee37fe97739d85991964371c1f3a745c00dd236;p=linux-2.6.git diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index a2c893a74..f12007b80 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -46,6 +46,29 @@ ipfrag_secret_interval - INTEGER for the hash secret) for IP fragments. Default: 600 +ipfrag_max_dist - INTEGER + ipfrag_max_dist is a non-negative integer value which defines the + maximum "disorder" which is allowed among fragments which share a + common IP source address. Note that reordering of packets is + not unusual, but if a large number of fragments arrive from a source + IP address while a particular fragment queue remains incomplete, it + probably indicates that one or more fragments belonging to that queue + have been lost. When ipfrag_max_dist is positive, an additional check + is done on fragments before they are added to a reassembly queue - if + ipfrag_max_dist (or more) fragments have arrived from a particular IP + address between additions to any IP fragment queue using that source + address, it's presumed that one or more fragments in the queue are + lost. The existing fragment queue will be dropped, and a new one + started. An ipfrag_max_dist value of zero disables this check. + + Using a very small value, e.g. 1 or 2, for ipfrag_max_dist can + result in unnecessarily dropping fragment queues when normal + reordering of packets occurs, which could lead to poor application + performance. Using a very large value, e.g. 50000, increases the + likelihood of incorrectly reassembling IP fragments that originate + from different IP datagrams, which could result in data corruption. + Default: 64 + INET peer storage: inet_peer_threshold - INTEGER @@ -78,6 +101,11 @@ inet_peer_gc_maxtime - INTEGER TCP variables: +tcp_abc - INTEGER + Controls Appropriate Byte Count defined in RFC3465. If set to + 0 then does congestion avoid once per ack. 1 is conservative + value, and 2 is more agressive. + 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 @@ -304,63 +332,12 @@ tcp_low_latency - BOOLEAN changed would be a Beowulf compute cluster. Default: 0 -tcp_westwood - BOOLEAN - Enable TCP Westwood+ congestion control algorithm. - TCP Westwood+ is a sender-side only modification of the TCP Reno - protocol stack that optimizes the performance of TCP congestion - control. It is based on end-to-end bandwidth estimation to set - congestion window and slow start threshold after a congestion - episode. Using this estimation, TCP Westwood+ adaptively sets a - slow start threshold and a congestion window which takes into - account the bandwidth used at the time congestion is experienced. - TCP Westwood+ significantly increases fairness wrt TCP Reno in - wired networks and throughput over wireless links. - Default: 0 - -tcp_vegas_cong_avoid - BOOLEAN - Enable TCP Vegas congestion avoidance algorithm. - TCP Vegas is a sender-side only change to TCP that anticipates - the onset of congestion by estimating the bandwidth. TCP Vegas - adjusts the sending rate by modifying the congestion - window. TCP Vegas should provide less packet loss, but it is - not as aggressive as TCP Reno. - Default:0 - -tcp_bic - BOOLEAN - Enable BIC TCP congestion control algorithm. - BIC-TCP is a sender-side only change that ensures a linear RTT - fairness under large windows while offering both scalability and - bounded TCP-friendliness. The protocol combines two schemes - called additive increase and binary search increase. When the - congestion window is large, additive increase with a large - increment ensures linear RTT fairness as well as good - scalability. Under small congestion windows, binary search - increase provides TCP friendliness. - Default: 0 - -tcp_bic_low_window - INTEGER - Sets the threshold window (in packets) where BIC TCP starts to - adjust the congestion window. Below this threshold BIC TCP behaves - the same as the default TCP Reno. - Default: 14 - -tcp_bic_fast_convergence - BOOLEAN - Forces BIC TCP to more quickly respond to changes in congestion - window. Allows two flows sharing the same connection to converge - more rapidly. - Default: 1 - -tcp_default_win_scale - INTEGER - Sets the minimum window scale TCP will negotiate for on all - conections. - Default: 7 - 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: 8 + Default: 3 tcp_frto - BOOLEAN Enables F-RTO, an enhanced recovery algorithm for TCP retransmission @@ -368,11 +345,23 @@ tcp_frto - BOOLEAN where packet loss is typically due to random radio interference rather than intermediate router congestion. +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. + 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_workaround_signed_windows - BOOLEAN + If set, assume no receipt of a window scaling option means the + remote TCP is broken and treats the window as a signed quantity. + If unset, assume the remote TCP is not broken even if we do + not receive a window scaling option from them. + Default: 0 + IP Variables: ip_local_port_range - 2 INTEGERS @@ -401,10 +390,14 @@ ip_dynaddr - BOOLEAN Default: 0 icmp_echo_ignore_all - BOOLEAN + If set non-zero, then the kernel will ignore all ICMP ECHO + requests sent to it. + Default: 0 + icmp_echo_ignore_broadcasts - BOOLEAN - If either is set to true, then the kernel will ignore either all - ICMP ECHO requests sent to it or just those to broadcast/multicast - addresses, respectively. + If set non-zero, then the kernel will ignore all ICMP ECHO and + TIMESTAMP requests sent to it via broadcast/multicast. + Default: 1 icmp_ratelimit - INTEGER Limit the maximal rates for sending ICMP packets whose type matches @@ -441,6 +434,23 @@ icmp_ignore_bogus_error_responses - BOOLEAN will avoid log file clutter. Default: FALSE +icmp_errors_use_inbound_ifaddr - BOOLEAN + + If zero, icmp error messages are sent with the primary address of + the exiting interface. + + If non-zero, the message will be sent with the primary address of + the interface that received the packet that caused the icmp error. + This is the behaviour network many administrators will expect from + a router. And it can make debugging complicated network layouts + much easier. + + Note that if no primary address exists for the interface selected, + then the primary address of the first non-loopback interface that + has one will be used regarldess of this setting. + + Default: 0 + igmp_max_memberships - INTEGER Change the maximum number of multicast groups we can subscribe to. Default: 20 @@ -616,6 +626,11 @@ arp_ignore - INTEGER The max value from conf/{all,interface}/arp_ignore is used when ARP request is received on the {interface} +arp_accept - BOOLEAN + Define behavior when gratuitous arp replies are received: + 0 - drop gratuitous arp frames + 1 - accept gratuitous arp frames + app_solicit - INTEGER The maximum number of probes to send to the user space ARP daemon via netlink before dropping back to multicast probes (see @@ -714,6 +729,33 @@ accept_ra - BOOLEAN Functional default: enabled if local forwarding is disabled. disabled if local forwarding is enabled. +accept_ra_defrtr - BOOLEAN + Learn default router in Router Advertisement. + + Functional default: enabled if accept_ra is enabled. + disabled if accept_ra is disabled. + +accept_ra_pinfo - BOOLEAN + Learn Prefix Inforamtion in Router Advertisement. + + Functional default: enabled if accept_ra is enabled. + disabled if accept_ra is disabled. + +accept_ra_rt_info_max_plen - INTEGER + Maximum prefix length of Route Information in RA. + + Route Information w/ prefix larger than or equal to this + variable shall be ignored. + + Functional default: 0 if accept_ra_rtr_pref is enabled. + -1 if accept_ra_rtr_pref is disabled. + +accept_ra_rtr_pref - BOOLEAN + Accept Router Preference in RA. + + Functional default: enabled if accept_ra is enabled. + disabled if accept_ra is disabled. + accept_redirects - BOOLEAN Accept Redirects. @@ -724,8 +766,8 @@ autoconf - BOOLEAN Autoconfigure addresses using Prefix Information in Router Advertisements. - Functional default: enabled if accept_ra is enabled. - disabled if accept_ra is disabled. + Functional default: enabled if accept_ra_pinfo is enabled. + disabled if accept_ra_pinfo is disabled. dad_transmits - INTEGER The amount of Duplicate Address Detection probes to send. @@ -768,6 +810,12 @@ mtu - INTEGER Default Maximum Transfer Unit Default: 1280 (IPv6 required minimum) +router_probe_interval - INTEGER + Minimum interval (in seconds) between Router Probing described + in RFC4191. + + Default: 60 + router_solicitation_delay - INTEGER Number of seconds to wait after interface is brought up before sending Router Solicitations.