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Diffstat (limited to 'Documentation/networking/ip-sysctl.txt')
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 485 |
1 files changed, 349 insertions, 136 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index d99940dcfc4..ab42c95f998 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -15,21 +15,78 @@ ip_default_ttl - INTEGER forwarded) IP packets. Should be between 1 and 255 inclusive. Default: 64 (as recommended by RFC1700) -ip_no_pmtu_disc - BOOLEAN - Disable Path MTU Discovery. - default FALSE +ip_no_pmtu_disc - INTEGER + Disable Path MTU Discovery. If enabled in mode 1 and a + fragmentation-required ICMP is received, the PMTU to this + destination will be set to min_pmtu (see below). You will need + to raise min_pmtu to the smallest interface MTU on your system + manually if you want to avoid locally generated fragments. + + In mode 2 incoming Path MTU Discovery messages will be + discarded. Outgoing frames are handled the same as in mode 1, + implicitly setting IP_PMTUDISC_DONT on every created socket. + + Mode 3 is a hardend pmtu discover mode. The kernel will only + accept fragmentation-needed errors if the underlying protocol + can verify them besides a plain socket lookup. Current + protocols for which pmtu events will be honored are TCP, SCTP + and DCCP as they verify e.g. the sequence number or the + association. This mode should not be enabled globally but is + only intended to secure e.g. name servers in namespaces where + TCP path mtu must still work but path MTU information of other + protocols should be discarded. If enabled globally this mode + could break other protocols. + + Possible values: 0-3 + Default: FALSE min_pmtu - INTEGER - default 562 - minimum discovered Path MTU + default 552 - minimum discovered Path MTU + +ip_forward_use_pmtu - BOOLEAN + By default we don't trust protocol path MTUs while forwarding + because they could be easily forged and can lead to unwanted + fragmentation by the router. + You only need to enable this if you have user-space software + which tries to discover path mtus by itself and depends on the + kernel honoring this information. This is normally not the + case. + Default: 0 (disabled) + Possible values: + 0 - disabled + 1 - enabled route/max_size - INTEGER Maximum number of routes allowed in the kernel. Increase this when using large numbers of interfaces and/or routes. +neigh/default/gc_thresh1 - INTEGER + Minimum number of entries to keep. Garbage collector will not + purge entries if there are fewer than this number. + Default: 128 + neigh/default/gc_thresh3 - INTEGER Maximum number of neighbor entries allowed. Increase this when using large numbers of interfaces and when communicating with large numbers of directly-connected peers. + Default: 1024 + +neigh/default/unres_qlen_bytes - INTEGER + The maximum number of bytes which may be used by packets + queued for each unresolved address by other network layers. + (added in linux 3.3) + Setting negative value is meaningless and will return error. + Default: 65536 Bytes(64KB) + +neigh/default/unres_qlen - INTEGER + The maximum number of packets which may be queued for each + unresolved address by other network layers. + (deprecated in linux 3.3) : use unres_qlen_bytes instead. + Prior to linux 3.3, the default value is 3 which may cause + unexpected packet loss. The current default value is calculated + according to default value of unres_qlen_bytes and true size of + packet. + Default: 31 mtu_expires - INTEGER Time, in seconds, that cached PMTU information is kept. @@ -38,12 +95,6 @@ min_adv_mss - INTEGER The advertised MSS depends on the first hop route MTU, but will never be lower than this setting. -rt_cache_rebuild_count - INTEGER - The per net-namespace route cache emergency rebuild threshold. - Any net-namespace having its route cache rebuilt due to - a hash bucket chain being too long more than this many times - will have its route caching disabled - IP Fragmentation: ipfrag_high_thresh - INTEGER @@ -106,16 +157,6 @@ inet_peer_maxttl - INTEGER when the number of entries in the pool is very small). Measured in seconds. -inet_peer_gc_mintime - INTEGER - Minimum interval between garbage collection passes. This interval is - in effect under high memory pressure on the pool. - Measured in seconds. - -inet_peer_gc_maxtime - INTEGER - Minimum interval between garbage collection passes. This interval is - in effect under low (or absent) memory pressure on the pool. - Measured in seconds. - TCP variables: somaxconn - INTEGER @@ -123,17 +164,6 @@ somaxconn - INTEGER 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 - in response to partial acknowledgments. - Possible values are: - 0 increase cwnd once per acknowledgment (no ABC) - 1 increase cwnd once per acknowledgment of full sized segment - 2 allow increase cwnd by two if acknowledgment is - of two segments to compensate for delayed acknowledgments. - Default: 0 (off) - 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 @@ -147,7 +177,7 @@ tcp_adv_win_scale - INTEGER (if tcp_adv_win_scale > 0) or bytes-bytes/2^(-tcp_adv_win_scale), if it is <= 0. Possible values are [-31, 31], inclusive. - Default: 2 + Default: 1 tcp_allowed_congestion_control - STRING Show/set the congestion control choices available to non-privileged @@ -160,6 +190,16 @@ tcp_app_win - INTEGER buffer. Value 0 is special, it means that nothing is reserved. Default: 31 +tcp_autocorking - BOOLEAN + Enable TCP auto corking : + When applications do consecutive small write()/sendmsg() system calls, + we try to coalesce these small writes as much as possible, to lower + total amount of sent packets. This is done if at least one prior + packet for the flow is waiting in Qdisc queues or device transmit + queue. Applications can still use TCP_CORK for optimal behavior + when they know how/when to uncork their sockets. + Default : 1 + tcp_available_congestion_control - STRING Shows the available congestion control choices that are registered. More congestion control algorithms may be available as modules, @@ -175,28 +215,43 @@ tcp_congestion_control - STRING 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_cookie_size - INTEGER - Default size of TCP Cookie Transactions (TCPCT) option, that may be - overridden on a per socket basis by the TCPCT socket option. - Values greater than the maximum (16) are interpreted as the maximum. - Values greater than zero and less than the minimum (8) are interpreted - as the minimum. Odd values are interpreted as the next even value. - Default: 0 (off). + For passive connections, the listener congestion control choice + is inherited. + [see setsockopt(listenfd, SOL_TCP, TCP_CONGESTION, "name" ...) ] tcp_dsack - BOOLEAN Allows TCP to send "duplicate" SACKs. -tcp_ecn - BOOLEAN - Enable Explicit Congestion Notification (ECN) in TCP. ECN is only - used when both ends of the TCP flow support it. It is useful to - avoid losses due to congestion (when the bottleneck router supports - ECN). +tcp_early_retrans - INTEGER + Enable Early Retransmit (ER), per RFC 5827. ER lowers the threshold + for triggering fast retransmit when the amount of outstanding data is + small and when no previously unsent data can be transmitted (such + that limited transmit could be used). Also controls the use of + Tail loss probe (TLP) that converts RTOs occurring due to tail + losses into fast recovery (draft-dukkipati-tcpm-tcp-loss-probe-01). + Possible values: + 0 disables ER + 1 enables ER + 2 enables ER but delays fast recovery and fast retransmit + by a fourth of RTT. This mitigates connection falsely + recovers when network has a small degree of reordering + (less than 3 packets). + 3 enables delayed ER and TLP. + 4 enables TLP only. + Default: 3 + +tcp_ecn - INTEGER + Control use of Explicit Congestion Notification (ECN) by TCP. + ECN is used only when both ends of the TCP connection indicate + support for it. This feature is useful in avoiding losses due + to congestion by allowing supporting routers to signal + congestion before having to drop packets. Possible values are: - 0 disable ECN - 1 ECN enabled - 2 Only server-side ECN enabled. If the other end does - not support ECN, behavior is like with ECN disabled. + 0 Disable ECN. Neither initiate nor accept ECN. + 1 Enable ECN when requested by incoming connections and + also request ECN on outgoing connection attempts. + 2 Enable ECN when requested by incoming connections + but do not request ECN on outgoing connections. Default: 2 tcp_fack - BOOLEAN @@ -204,47 +259,23 @@ tcp_fack - BOOLEAN 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 - by our side. Peer can be broken and never close its side, - or even died unexpectedly. Default value is 60sec. - Usual value used in 2.2 was 180 seconds, you may restore - it, but remember that if your machine is even underloaded WEB server, - you risk to overflow memory with kilotons of dead sockets, - FIN-WAIT-2 sockets are less dangerous than FIN-WAIT-1, - because they eat maximum 1.5K of memory, but they tend - to live longer. Cf. tcp_max_orphans. + The length of time an orphaned (no longer referenced by any + application) connection will remain in the FIN_WAIT_2 state + before it is aborted at the local end. While a perfectly + valid "receive only" state for an un-orphaned connection, an + orphaned connection in FIN_WAIT_2 state could otherwise wait + forever for the remote to close its end of the connection. + Cf. tcp_max_orphans + Default: 60 seconds tcp_frto - INTEGER - Enables Forward RTO-Recovery (F-RTO) defined in RFC4138. + Enables Forward RTO-Recovery (F-RTO) defined in RFC5682. F-RTO is 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. F-RTO is sender-side - 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 - interacts badly with the packet counting of the SACK enabled TCP - flow. - -tcp_frto_response - INTEGER - When F-RTO has detected that a TCP retransmission timeout was - spurious (i.e, the timeout would have been avoided had TCP set a - longer retransmission timeout), TCP has several options what to do - next. Possible values are: - 0 Rate halving based; a smooth and conservative response, - results in halved cwnd and ssthresh after one RTT - 1 Very conservative response; not recommended because even - though being valid, it interacts poorly with the rest of - Linux TCP, halves cwnd and ssthresh immediately - 2 Aggressive response; undoes congestion control measures - that are now known to be unnecessary (ignoring the - possibility of a lost retransmission that would require - TCP to be more cautious), cwnd and ssthresh are restored - to the values prior timeout - Default: 0 (rate halving based) + timeouts. It is particularly beneficial in networks where the + RTT fluctuates (e.g., wireless). F-RTO is sender-side only + modification. It does not require any support from the peer. + + By default it's enabled with a non-zero value. 0 disables F-RTO. tcp_keepalive_time - INTEGER How often TCP sends out keepalive messages when keepalive is enabled. @@ -281,11 +312,11 @@ tcp_max_orphans - INTEGER up to ~64K of unswappable memory. tcp_max_syn_backlog - INTEGER - Maximal number of remembered connection requests, which are - still did not receive an acknowledgment from connecting client. - Default value is 1024 for systems with more than 128Mb of memory, - and 128 for low memory machines. If server suffers of overload, - try to increase this number. + Maximal number of remembered connection requests, which have not + received an acknowledgment from connecting client. + The minimal value is 128 for low memory machines, and it will + increase in proportion to the memory of machine. + If server suffers from overload, try increasing this number. tcp_max_tw_buckets - INTEGER Maximal number of timewait sockets held by system simultaneously. @@ -335,7 +366,7 @@ tcp_orphan_retries - INTEGER when RTO retransmissions remain unacknowledged. See tcp_retries2 for more details. - The default value is 7. + The default value is 8. If your machine is a loaded WEB server, you should think about lowering this value, such sockets may consume significant resources. Cf. tcp_max_orphans. @@ -383,7 +414,7 @@ tcp_rmem - vector of 3 INTEGERs: min, default, max min: Minimal size of receive buffer used by TCP sockets. It is guaranteed to each TCP socket, even under moderate memory pressure. - Default: 8K + Default: 1 page default: initial size of receive buffer used by TCP sockets. This value overrides net.core.rmem_default used by other protocols. @@ -396,7 +427,7 @@ tcp_rmem - vector of 3 INTEGERs: min, default, max 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. + Default: between 87380B and 6MB, depending on RAM size. tcp_sack - BOOLEAN Enable select acknowledgments (SACKS). @@ -417,13 +448,15 @@ tcp_stdurg - BOOLEAN 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. + is 5, which corresponds to 31seconds till the last retransmission + with the current initial RTO of 1second. With this the final timeout + for a passive TCP connection will happen after 63seconds. tcp_syncookies - BOOLEAN - Only valid when the kernel was compiled with CONFIG_SYNCOOKIES + Only valid when the kernel was compiled with CONFIG_SYN_COOKIES Send out syncookies when the syn backlog queue of a socket overflows. This is to prevent against the common 'SYN flood attack' - Default: FALSE + Default: 1 Note, that syncookies is fallback facility. It MUST NOT be used to help highly loaded servers to stand @@ -440,14 +473,57 @@ tcp_syncookies - BOOLEAN SYN flood warnings in logs not being really flooded, your server is seriously misconfigured. + If you want to test which effects syncookies have to your + network connections you can set this knob to 2 to enable + unconditionally generation of syncookies. + +tcp_fastopen - INTEGER + Enable TCP Fast Open feature (draft-ietf-tcpm-fastopen) to send data + in the opening SYN packet. To use this feature, the client application + must use sendmsg() or sendto() with MSG_FASTOPEN flag rather than + connect() to perform a TCP handshake automatically. + + The values (bitmap) are + 1: Enables sending data in the opening SYN on the client w/ MSG_FASTOPEN. + 2: Enables TCP Fast Open on the server side, i.e., allowing data in + a SYN packet to be accepted and passed to the application before + 3-way hand shake finishes. + 4: Send data in the opening SYN regardless of cookie availability and + without a cookie option. + 0x100: Accept SYN data w/o validating the cookie. + 0x200: Accept data-in-SYN w/o any cookie option present. + 0x400/0x800: Enable Fast Open on all listeners regardless of the + TCP_FASTOPEN socket option. The two different flags designate two + different ways of setting max_qlen without the TCP_FASTOPEN socket + option. + + Default: 1 + + Note that the client & server side Fast Open flags (1 and 2 + respectively) must be also enabled before the rest of flags can take + effect. + + See include/net/tcp.h and the code for more details. + 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. + is 6, which corresponds to 63seconds till the last retransmission + with the current initial RTO of 1second. With this the final timeout + for an active TCP connection attempt will happen after 127seconds. tcp_timestamps - BOOLEAN Enable timestamps as defined in RFC1323. +tcp_min_tso_segs - INTEGER + Minimal number of segments per TSO frame. + Since linux-3.12, TCP does an automatic sizing of TSO frames, + depending on flow rate, instead of filling 64Kbytes packets. + For specific usages, it's possible to force TCP to build big + TSO frames. Note that TCP stack might split too big TSO packets + if available window is too small. + Default: 2 + tcp_tso_win_divisor - INTEGER This allows control over what percentage of the congestion window can be consumed by a single TSO frame. @@ -472,7 +548,7 @@ tcp_window_scaling - BOOLEAN tcp_wmem - vector of 3 INTEGERs: min, default, max 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: 1 page default: initial size of send buffer used by TCP sockets. This value overrides net.core.wmem_default used by other protocols. @@ -486,6 +562,19 @@ tcp_wmem - vector of 3 INTEGERs: min, default, max this value is ignored. Default: between 64K and 4MB, depending on RAM size. +tcp_notsent_lowat - UNSIGNED INTEGER + A TCP socket can control the amount of unsent bytes in its write queue, + thanks to TCP_NOTSENT_LOWAT socket option. poll()/select()/epoll() + reports POLLOUT events if the amount of unsent bytes is below a per + socket value, and if the write queue is not full. sendmsg() will + also not add new buffers if the limit is hit. + + This global variable controls the amount of unsent data for + sockets not using TCP_NOTSENT_LOWAT. For these sockets, a change + to the global variable has immediate effect. + + Default: UINT_MAX (0xFFFFFFFF) + 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. @@ -523,6 +612,22 @@ tcp_thin_dupack - BOOLEAN Documentation/networking/tcp-thin.txt Default: 0 +tcp_limit_output_bytes - INTEGER + Controls TCP Small Queue limit per tcp socket. + TCP bulk sender tends to increase packets in flight until it + gets losses notifications. With SNDBUF autotuning, this can + result in a large amount of packets queued in qdisc/device + on the local machine, hurting latency of other flows, for + typical pfifo_fast qdiscs. + tcp_limit_output_bytes limits the number of bytes on qdisc + or device to reduce artificial RTT/cwnd and reduce bufferbloat. + Default: 131072 + +tcp_challenge_ack_limit - INTEGER + Limits number of Challenge ACK sent per second, as recommended + in RFC 5961 (Improving TCP's Robustness to Blind In-Window Attacks) + Default: 100 + UDP variables: udp_mem - vector of 3 INTEGERs: min, pressure, max @@ -542,13 +647,13 @@ udp_rmem_min - INTEGER Minimal size of receive buffer used by UDP sockets in moderation. Each UDP socket is able to use the size for receiving data, even if total pages of UDP sockets exceed udp_mem pressure. The unit is byte. - Default: 4096 + Default: 1 page udp_wmem_min - INTEGER Minimal size of send buffer used by UDP sockets in moderation. Each UDP socket is able to use the size for sending data, even if total pages of UDP sockets exceed udp_mem pressure. The unit is byte. - Default: 4096 + Default: 1 page CIPSOv4 Variables: @@ -590,15 +695,8 @@ IP Variables: ip_local_port_range - 2 INTEGERS Defines the local port range that is used by TCP and UDP to choose the local port. The first number is the first, the - second the last local port number. Default value depends on - amount of memory available on the system: - > 128Mb 32768-61000 - < 128Mb 1024-4999 or even less. - This number defines number of active connections, which this - system can issue simultaneously to systems not supporting - TCP extensions (timestamps). With tcp_tw_recycle enabled - (i.e. by default) range 1024-4999 is enough to issue up to - 2000 connections per second to systems supporting timestamps. + second the last local port number. The default values are + 32768 and 61000 respectively. ip_local_reserved_ports - list of comma separated ranges Specify the ports which are reserved for known third-party @@ -643,6 +741,15 @@ ip_dynaddr - BOOLEAN occurs. Default: 0 +ip_early_demux - BOOLEAN + Optimize input packet processing down to one demux for + certain kinds of local sockets. Currently we only do this + for established TCP sockets. + + It may add an additional cost for pure routing workloads that + reduces overall throughput, in such case you should disable it. + Default: 1 + icmp_echo_ignore_all - BOOLEAN If set non-zero, then the kernel will ignore all ICMP ECHO requests sent to it. @@ -687,7 +794,7 @@ icmp_ignore_bogus_error_responses - BOOLEAN frames. Such violations are normally logged via a kernel warning. If this is set to TRUE, the kernel will not give such warnings, which will avoid log file clutter. - Default: FALSE + Default: 1 icmp_errors_use_inbound_ifaddr - BOOLEAN @@ -836,9 +943,19 @@ accept_source_route - BOOLEAN FALSE (host) accept_local - BOOLEAN - Accept packets with local source addresses. In combination with - suitable routing, this can be used to direct packets between two - local interfaces over the wire and have them accepted properly. + Accept packets with local source addresses. In combination + with suitable routing, this can be used to direct packets + between two local interfaces over the wire and have them + accepted properly. + + rp_filter must be set to a non-zero value in order for + accept_local to have an effect. + + default FALSE + +route_localnet - BOOLEAN + Do not consider loopback addresses as martian source or destination + while routing. This enables the use of 127/8 for local routing purposes. default FALSE rp_filter - INTEGER @@ -961,6 +1078,20 @@ disable_policy - BOOLEAN disable_xfrm - BOOLEAN Disable IPSEC encryption on this interface, whatever the policy +igmpv2_unsolicited_report_interval - INTEGER + The interval in milliseconds in which the next unsolicited + IGMPv1 or IGMPv2 report retransmit will take place. + Default: 10000 (10 seconds) + +igmpv3_unsolicited_report_interval - INTEGER + The interval in milliseconds in which the next unsolicited + IGMPv3 report retransmit will take place. + Default: 1000 (1 seconds) + +promote_secondaries - BOOLEAN + When a primary IP address is removed from this interface + promote a corresponding secondary IP address instead of + removing all the corresponding secondary IP addresses. tag - INTEGER @@ -991,7 +1122,22 @@ bindv6only - BOOLEAN TRUE: disable IPv4-mapped address feature FALSE: enable IPv4-mapped address feature - Default: FALSE (as specified in RFC2553bis) + Default: FALSE (as specified in RFC3493) + +flowlabel_consistency - BOOLEAN + Protect the consistency (and unicity) of flow label. + You have to disable it to use IPV6_FL_F_REFLECT flag on the + flow label manager. + TRUE: enabled + FALSE: disabled + Default: TRUE + +anycast_src_echo_reply - BOOLEAN + Controls the use of anycast addresses as source addresses for ICMPv6 + echo reply + TRUE: enabled + FALSE: disabled + Default: FALSE IPv6 Fragmentation: @@ -1041,9 +1187,14 @@ conf/interface/*: The functional behaviour for certain settings is different depending on whether local forwarding is enabled or not. -accept_ra - BOOLEAN +accept_ra - INTEGER Accept Router Advertisements; autoconfigure using them. + It also determines whether or not to transmit Router + Solicitations. If and only if the functional setting is to + accept Router Advertisements, Router Solicitations will be + transmitted. + Possible values are: 0 Do not accept Router Advertisements. 1 Accept Router Advertisements if forwarding is disabled. @@ -1105,7 +1256,7 @@ dad_transmits - INTEGER The amount of Duplicate Address Detection probes to send. Default: 1 -forwarding - BOOLEAN +forwarding - INTEGER Configure interface-specific Host/Router behaviour. Note: It is recommended to have the same setting on all @@ -1114,14 +1265,14 @@ forwarding - BOOLEAN Possible values are: 0 Forwarding disabled 1 Forwarding enabled - 2 Forwarding enabled (Hybrid Mode) FALSE (0): By default, Host behaviour is assumed. This means: 1. IsRouter flag is not set in Neighbour Advertisements. - 2. Router Solicitations are being sent when necessary. + 2. If accept_ra is TRUE (default), transmit Router + Solicitations. 3. If accept_ra is TRUE (default), accept Router Advertisements (and do autoconfiguration). 4. If accept_redirects is TRUE (default), accept Redirects. @@ -1132,16 +1283,10 @@ forwarding - BOOLEAN This means exactly the reverse from the above: 1. IsRouter flag is set in Neighbour Advertisements. - 2. Router Solicitations are not sent. + 2. Router Solicitations are not sent unless accept_ra is 2. 3. Router Advertisements are ignored unless accept_ra is 2. 4. Redirects are ignored. - TRUE (2): - - Hybrid mode. Same behaviour as TRUE, except for: - - 2. Router Solicitations are being sent when necessary. - Default: 0 (disabled) if global forwarding is disabled (default), otherwise 1 (enabled). @@ -1248,6 +1393,33 @@ force_tllao - BOOLEAN race condition where the sender deletes the cached link-layer address prior to receiving a response to a previous solicitation." +ndisc_notify - BOOLEAN + Define mode for notification of address and device changes. + 0 - (default): do nothing + 1 - Generate unsolicited neighbour advertisements when device is brought + up or hardware address changes. + +mldv1_unsolicited_report_interval - INTEGER + The interval in milliseconds in which the next unsolicited + MLDv1 report retransmit will take place. + Default: 10000 (10 seconds) + +mldv2_unsolicited_report_interval - INTEGER + The interval in milliseconds in which the next unsolicited + MLDv2 report retransmit will take place. + Default: 1000 (1 second) + +force_mld_version - INTEGER + 0 - (default) No enforcement of a MLD version, MLDv1 fallback allowed + 1 - Enforce to use MLD version 1 + 2 - Enforce to use MLD version 2 + +suppress_frag_ndisc - INTEGER + Control RFC 6980 (Security Implications of IPv6 Fragmentation + with IPv6 Neighbor Discovery) behavior: + 1 - (default) discard fragmented neighbor discovery packets + 0 - allow fragmented neighbor discovery packets + icmp/*: ratelimit - INTEGER Limit the maximal rates for sending ICMPv6 packets. @@ -1281,13 +1453,22 @@ bridge-nf-call-ip6tables - BOOLEAN bridge-nf-filter-vlan-tagged - BOOLEAN 1 : pass bridged vlan-tagged ARP/IP/IPv6 traffic to {arp,ip,ip6}tables. 0 : disable this. - Default: 1 + Default: 0 bridge-nf-filter-pppoe-tagged - BOOLEAN 1 : pass bridged pppoe-tagged IP/IPv6 traffic to {ip,ip6}tables. 0 : disable this. - Default: 1 + Default: 0 +bridge-nf-pass-vlan-input-dev - BOOLEAN + 1: if bridge-nf-filter-vlan-tagged is enabled, try to find a vlan + interface on the bridge and set the netfilter input device to the vlan. + This allows use of e.g. "iptables -i br0.1" and makes the REDIRECT + target work with vlan-on-top-of-bridge interfaces. When no matching + vlan interface is found, or this switch is off, the input device is + set to the bridge interface. + 0: disable bridge netfilter vlan interface lookup. + Default: 0 proc/sys/net/sctp/* Variables: @@ -1369,6 +1550,20 @@ path_max_retrans - INTEGER Default: 5 +pf_retrans - INTEGER + The number of retransmissions that will be attempted on a given path + before traffic is redirected to an alternate transport (should one + exist). Note this is distinct from path_max_retrans, as a path that + passes the pf_retrans threshold can still be used. Its only + deprioritized when a transmission path is selected by the stack. This + setting is primarily used to enable fast failover mechanisms without + having to reduce path_max_retrans to a very low value. See: + http://www.ietf.org/id/draft-nishida-tsvwg-sctp-failover-05.txt + for details. Note also that a value of pf_retrans > path_max_retrans + disables this feature + + Default: 0 + rto_initial - INTEGER The initial round trip timeout value in milliseconds that will be used in calculating round trip times. This is the initial time interval @@ -1416,6 +1611,20 @@ cookie_preserve_enable - BOOLEAN Default: 1 +cookie_hmac_alg - STRING + Select the hmac algorithm used when generating the cookie value sent by + a listening sctp socket to a connecting client in the INIT-ACK chunk. + Valid values are: + * md5 + * sha1 + * none + Ability to assign md5 or sha1 as the selected alg is predicated on the + configuration of those algorithms at build time (CONFIG_CRYPTO_MD5 and + CONFIG_CRYPTO_SHA1). + + Default: Dependent on configuration. MD5 if available, else SHA1 if + available, else none. + rcvbuf_policy - INTEGER Determines if the receive buffer is attributed to the socket or to association. SCTP supports the capability to create multiple @@ -1428,7 +1637,7 @@ rcvbuf_policy - INTEGER blocking. 1: rcvbuf space is per association - 0: recbuf space is per socket + 0: rcvbuf space is per socket Default: 0 @@ -1454,10 +1663,17 @@ sctp_mem - vector of 3 INTEGERs: min, pressure, max Default is calculated at boot time from amount of available memory. sctp_rmem - vector of 3 INTEGERs: min, default, max - See tcp_rmem for a description. + Only the first value ("min") is used, "default" and "max" are + ignored. + + min: Minimal size of receive buffer used by SCTP socket. + It is guaranteed to each SCTP socket (but not association) even + under moderate memory pressure. + + Default: 1 page sctp_wmem - vector of 3 INTEGERs: min, default, max - See tcp_wmem for a description. + Currently this tunable has no effect. addr_scope_policy - INTEGER Control IPv4 address scoping - draft-stewart-tsvwg-sctp-ipv4-00 @@ -1471,11 +1687,8 @@ addr_scope_policy - INTEGER /proc/sys/net/core/* -dev_weight - INTEGER - The maximum number of packets that kernel can handle on a NAPI - interrupt, it's a Per-CPU variable. + Please see: Documentation/sysctl/net.txt for descriptions of these entries. - Default: 64 /proc/sys/net/unix/* max_dgram_qlen - INTEGER |