/proc/sys/net/ipv4/* Variables: ??ip_forward - BOOLEAN ?? 0 - disabled (default) ?? not 0 - enabled ?? Forward Packets between interfaces. ?? This variable is special, its change resets all configuration ?? parameters to their default state (RFC1122 for hosts, RFC1812 ?? for routers) ??ip_default_ttl - INTEGER ?? default 64 ??ip_no_pmtu_disc - BOOLEAN ?? Disable Path MTU Discovery. ?? default FALSE ??min_pmtu - INTEGER ?? default 562 - minimum discovered Path MTU ??mtu_expires - INTEGER ?? Time, in seconds, that cached PMTU information is kept. ??min_adv_mss - INTEGER ?? The advertised MSS depends on the first hop route MTU, but will ?? never be lower than this setting. ?? ??IP Fragmentation: ??ipfrag_high_thresh - INTEGER ?? Maximum memory used to reassemble IP fragments. When ?? ipfrag_high_thresh bytes of memory is allocated for this purpose, ?? the fragment handler will toss packets until ipfrag_low_thresh ?? is reached. ??ipfrag_low_thresh - INTEGER ?? See ipfrag_high_thresh ??ipfrag_time - INTEGER ?? Time in seconds to keep an IP fragment in memory. ??ipfrag_secret_interval - INTEGER ?? Regeneration interval (in seconds) of the hash secret (or lifetime ?? for the hash secret) for IP fragments. ?? Default: 600 ?? ??INET peer storage: ??inet_peer_threshold - INTEGER ?? The approximate size of the storage. Starting from this threshold ?? entries will be thrown aggressively. This threshold also determines ?? entries' time-to-live and time intervals between garbage collection ?? passes. More entries, less time-to-live, less GC interval. ??inet_peer_minttl - INTEGER ?? Minimum time-to-live of entries. Should be enough to cover fragment ?? time-to-live on the reassembling side. This minimum time-to-live is ?? guaranteed if the pool size is less than inet_peer_threshold. ?? Measured in jiffies(1). ??inet_peer_maxttl - INTEGER ?? Maximum time-to-live of entries. Unused entries will expire after ?? this period of time if there is no memory pressure on the pool (i.e. ?? when the number of entries in the pool is very small). ?? Measured in jiffies(1). ??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 jiffies(1). ??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 jiffies(1). ?? ??TCP variables: ??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_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_keepalive_time - INTEGER ?? How often TCP sends out keepalive messages when keepalive is enabled. ?? Default: 2hours. ??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_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_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_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_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. ??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_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_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_max_orphans - INTEGER ?? Maximal number of TCP sockets not attached to any user file handle, ?? held by system. If this number is exceeded orphaned connections are ?? reset immediately and warning is printed. This limit exists ?? only to prevent simple DoS attacks, you _must_ not rely on this ?? or lower the limit artificially, but rather increase it ?? (probably, after increasing installed memory), ?? if network conditions require more than default value, ?? and tune network services to linger and kill such states ?? 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. ?? 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. ??tcp_window_scaling - BOOLEAN ?? Enable window scaling as defined in RFC1323. ??tcp_timestamps - BOOLEAN ?? Enable timestamps as defined in RFC1323. ??tcp_sack - BOOLEAN ?? Enable select acknowledgments (SACKS). ??tcp_fack - BOOLEAN ?? Enable FACK congestion avoidance and fast retransmission. ?? The value is not used, if tcp_sack is not enabled. ??tcp_dsack - BOOLEAN ?? Allows TCP to send "duplicate" SACKs. ??tcp_ecn - BOOLEAN ?? Enable Explicit Congestion Notification in TCP. ??tcp_reordering - INTEGER ?? Maximal reordering of packets in a TCP stream. ?? Default: 3 ??tcp_retrans_collapse - BOOLEAN ?? Bug-to-bug compatibility with some broken printers. ?? 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 ?? 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_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: default 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 ?? less for default tcp_app_win. See below about these variables. ?? 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. ??tcp_mem - vector of 3 INTEGERs: min, pressure, max ?? low: below this number of pages TCP is not bothered about its ?? memory appetite. ?? 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 "low". ?? high: number of pages allowed for queueing by all TCP sockets. ?? Defaults are calculated at boot time from amount of available ?? memory. ??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_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_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_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_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 ??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. ??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. ?? ??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. ??ip_nonlocal_bind - BOOLEAN ?? If set, allows processes to bind() to non-local IP addresses, ?? which can be quite useful - but may break some applications. ?? Default: 0 ??ip_dynaddr - BOOLEAN ?? If set non-zero, enables support for dynamic addresses. ?? If set to a non-zero value larger than 1, a kernel log ?? message will be printed when dynamic address rewriting ?? occurs. ?? Default: 0 ??icmp_echo_ignore_all - BOOLEAN ??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. ??icmp_ratelimit - INTEGER ?? Limit the maximal rates for sending ICMP packets whose type matches ?? icmp_ratemask (see below) to specific targets. ?? 0 to disable any limiting, otherwise the maximal rate in jiffies(1) ?? Default: 100 ??icmp_ratemask - INTEGER ?? Mask made of ICMP types for which rates are being limited. ?? Significant bits: IHGFEDCBA9876543210 ?? Default mask: 0000001100000011000 (6168) ?? Bit definitions (see include/linux/icmp.h): ?? 0 Echo Reply ?? 3 Destination Unreachable * ?? 4 Source Quench * ?? 5 Redirect ?? 8 Echo Request ?? B Time Exceeded * ?? C Parameter Problem * ?? D Timestamp Request ?? E Timestamp Reply ?? F Info Request ?? G Info Reply ?? H Address Mask Request ?? I Address Mask Reply ?? * These are rate limited by default (see default mask above) ??icmp_ignore_bogus_error_responses - BOOLEAN ?? Some routers violate RFC1122 by sending bogus responses to broadcast ?? 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 ??igmp_max_memberships - INTEGER ?? Change the maximum number of multicast groups we can subscribe to. ?? Default: 20 ??conf/interface/* changes special settings per interface (where "interface" is ?? the name of your network interface) ??conf/all/* is special, changes the settings for all interfaces ??log_martians - BOOLEAN ?? Log packets with impossible addresses to kernel log. ?? log_martians for the interface will be enabled if at least one of ?? conf/{all,interface}/log_martians is set to TRUE, ?? it will be disabled otherwise ??accept_redirects - BOOLEAN ?? Accept ICMP redirect messages. ?? accept_redirects for the interface will be enabled if: ?? - both conf/{all,interface}/accept_redirects are TRUE in the case forwarding ?? for the interface is enabled ?? or ?? - at least one of conf/{all,interface}/accept_redirects is TRUE in the case ?? forwarding for the interface is disabled ?? accept_redirects for the interface will be disabled otherwise ?? default TRUE (host) ?? FALSE (router) ??forwarding - BOOLEAN ?? Enable IP forwarding on this interface. ??mc_forwarding - BOOLEAN ?? Do multicast routing. The kernel needs to be compiled with CONFIG_MROUTE ?? and a multicast routing daemon is required. ?? conf/all/mc_forwarding must also be set to TRUE to enable multicast routing ?? for the interface ??medium_id - INTEGER ?? Integer value used to differentiate the devices by the medium they ?? are attached to. Two devices can have different id values when ?? the broadcast packets are received only on one of them. ?? The default value 0 means that the device is the only interface ?? to its medium, value of -1 means that medium is not known. ?? Currently, it is used to change the proxy_arp behavior: ?? the proxy_arp feature is enabled for packets forwarded between ?? two devices attached to different media. ??proxy_arp - BOOLEAN ?? Do proxy arp. ?? proxy_arp for the interface will be enabled if at least one of ?? conf/{all,interface}/proxy_arp is set to TRUE, ?? it will be disabled otherwise ??shared_media - BOOLEAN ?? Send(router) or accept(host) RFC1620 shared media redirects. ?? Overrides ip_secure_redirects. ?? shared_media for the interface will be enabled if at least one of ?? conf/{all,interface}/shared_media is set to TRUE, ?? it will be disabled otherwise ?? default TRUE ??secure_redirects - BOOLEAN ?? Accept ICMP redirect messages only for gateways, ?? listed in default gateway list. ?? secure_redirects for the interface will be enabled if at least one of ?? conf/{all,interface}/secure_redirects is set to TRUE, ?? it will be disabled otherwise ?? default TRUE ??send_redirects - BOOLEAN ?? Send redirects, if router. ?? send_redirects for the interface will be enabled if at least one of ?? conf/{all,interface}/send_redirects is set to TRUE, ?? it will be disabled otherwise ?? Default: TRUE ??bootp_relay - BOOLEAN ?? Accept packets with source address 0.b.c.d destined ?? not to this host as local ones. It is supposed, that ?? BOOTP relay daemon will catch and forward such packets. ?? conf/all/bootp_relay must also be set to TRUE to enable BOOTP relay ?? for the interface ?? default FALSE ?? Not Implemented Yet. ??accept_source_route - BOOLEAN ?? Accept packets with SRR option. ?? conf/all/accept_source_route must also be set to TRUE to accept packets ?? with SRR option on the interface ?? default TRUE (router) ?? FALSE (host) ??rp_filter - BOOLEAN ?? 1 - do source validation by reversed path, as specified in RFC1812 ?? Recommended option for single homed hosts and stub network ?? routers. Could cause troubles for complicated (not loop free) ?? networks running a slow unreliable protocol (sort of RIP), ?? or using static routes. ?? 0 - No source validation. ?? conf/all/rp_filter must also be set to TRUE to do source validation ?? on the interface ?? Default value is 0. Note that some distributions enable it ?? in startup scripts. ??arp_filter - BOOLEAN ?? 1 - Allows you to have multiple network interfaces on the same ?? subnet, and have the ARPs for each interface be answered ?? based on whether or not the kernel would route a packet from ?? the ARP'd IP out that interface (therefore you must use source ?? based routing for this to work). In other words it allows control ?? of which cards (usually 1) will respond to an arp request. ?? 0 - (default) The kernel can respond to arp requests with addresses ?? from other interfaces. This may seem wrong but it usually makes ?? sense, because it increases the chance of successful communication. ?? IP addresses are owned by the complete host on Linux, not by ?? particular interfaces. Only for more complex setups like load- ?? balancing, does this behaviour cause problems. ?? arp_filter for the interface will be enabled if at least one of ?? conf/{all,interface}/arp_filter is set to TRUE, ?? it will be disabled otherwise ??arp_announce - INTEGER ?? Define different restriction levels for announcing the local ?? source IP address from IP packets in ARP requests sent on ?? interface: ?? 0 - (default) Use any local address, configured on any interface ?? 1 - Try to avoid local addresses that are not in the target's ?? subnet for this interface. This mode is useful when target ?? hosts reachable via this interface require the source IP ?? address in ARP requests to be part of their logical network ?? configured on the receiving interface. When we generate the ?? request we will check all our subnets that include the ?? target IP and will preserve the source address if it is from ?? such subnet. If there is no such subnet we select source ?? address according to the rules for level 2. ?? 2 - Always use the best local address for this target. ?? In this mode we ignore the source address in the IP packet ?? and try to select local address that we prefer for talks with ?? the target host. Such local address is selected by looking ?? for primary IP addresses on all our subnets on the outgoing ?? interface that include the target IP address. If no suitable ?? local address is found we select the first local address ?? we have on the outgoing interface or on all other interfaces, ?? with the hope we will receive reply for our request and ?? even sometimes no matter the source IP address we announce. ?? The max value from conf/{all,interface}/arp_announce is used. ?? Increasing the restriction level gives more chance for ?? receiving answer from the resolved target while decreasing ?? the level announces more valid sender's information. ??arp_ignore - INTEGER ?? Define different modes for sending replies in response to ?? received ARP requests that resolve local target IP addresses: ?? 0 - (default): reply for any local target IP address, configured ?? on any interface ?? 1 - reply only if the target IP address is local address ?? configured on the incoming interface ?? 2 - reply only if the target IP address is local address ?? configured on the incoming interface and both with the ?? sender's IP address are part from same subnet on this interface ?? 3 - do not reply for local addresses configured with scope host, ?? only resolutions for global and link addresses are replied ?? 4-7 - reserved ?? 8 - do not reply for all local addresses ?? The max value from conf/{all,interface}/arp_ignore is used ?? when ARP request is received on the {interface} ??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 ?? mcast_solicit). Defaults to 0. ??disable_policy - BOOLEAN ?? Disable IPSEC policy (SPD) for this interface ??disable_xfrm - BOOLEAN ?? Disable IPSEC encryption on this interface, whatever the policy ??tag - INTEGER ?? Allows you to write a number, which can be used as required. ?? Default value is 0. ??(1) Jiffie: internal timeunit for the kernel. On the i386 1/100s, on the ??Alpha 1/1024s. See the HZ define in /usr/include/asm/param.h for the exact ??value on your system. ??Alexey Kuznetsov. ??kuznet@ms2.inr.ac.ru ??Updated by: ??Andi Kleen ??ak@muc.de ??Nicolas Delon ??delon.nicolas@wanadoo.fr ?? ??/proc/sys/net/ipv6/* Variables: ??IPv6 has no global variables such as tcp_*. tcp_* settings under ipv4/ also ??apply to IPv6 [XXX?]. ??bindv6only - BOOLEAN ?? Default value for IPV6_V6ONLY socket option, ?? which restricts use of the IPv6 socket to IPv6 communication ?? only. ?? TRUE: disable IPv4-mapped address feature ?? FALSE: enable IPv4-mapped address feature ?? Default: FALSE (as specified in RFC2553bis) ?? ??IPv6 Fragmentation: ??ip6frag_high_thresh - INTEGER ?? Maximum memory used to reassemble IPv6 fragments. When ?? ip6frag_high_thresh bytes of memory is allocated for this purpose, ?? the fragment handler will toss packets until ip6frag_low_thresh ?? is reached. ??ip6frag_low_thresh - INTEGER ?? See ip6frag_high_thresh ??ip6frag_time - INTEGER ?? Time in seconds to keep an IPv6 fragment in memory. ??ip6frag_secret_interval - INTEGER ?? Regeneration interval (in seconds) of the hash secret (or lifetime ?? for the hash secret) for IPv6 fragments. ?? Default: 600 ??conf/default/*: ?? Change the interface-specific default settings. ??conf/all/*: ?? Change all the interface-specific settings. ?? [XXX: Other special features than forwarding?] ??conf/all/forwarding - BOOLEAN ?? Enable global IPv6 forwarding between all interfaces. ?? IPv4 and IPv6 work differently here; e.g. netfilter must be used ?? to control which interfaces may forward packets and which not. ?? This also sets all interfaces' Host/Router setting ?? 'forwarding' to the specified value. See below for details. ?? This referred to as global forwarding. ??conf/interface/*: ?? Change special settings per interface. ?? The functional behaviour for certain settings is different ?? depending on whether local forwarding is enabled or not. ??accept_ra - BOOLEAN ?? Accept Router Advertisements; autoconfigure using them. ?? Functional default: enabled if local forwarding is disabled. ?? disabled if local forwarding is enabled. ??accept_redirects - BOOLEAN ?? Accept Redirects. ?? Functional default: enabled if local forwarding is disabled. ?? disabled if local forwarding is enabled. ??autoconf - BOOLEAN ?? Autoconfigure addresses using Prefix Information in Router ?? Advertisements. ?? Functional default: enabled if accept_ra is enabled. ?? disabled if accept_ra is disabled. ??dad_transmits - INTEGER ?? The amount of Duplicate Address Detection probes to send. ?? Default: 1 ??forwarding - BOOLEAN ?? Configure interface-specific Host/Router behaviour. ?? Note: It is recommended to have the same setting on all ?? interfaces; mixed router/host scenarios are rather uncommon. ?? FALSE: ?? 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. ?? 3. If accept_ra is TRUE (default), accept Router ?? Advertisements (and do autoconfiguration). ?? 4. If accept_redirects is TRUE (default), accept Redirects. ?? TRUE: ?? If local forwarding is enabled, Router behaviour is assumed. ?? This means exactly the reverse from the above: ?? 1. IsRouter flag is set in Neighbour Advertisements. ?? 2. Router Solicitations are not sent. ?? 3. Router Advertisements are ignored. ?? 4. Redirects are ignored. ?? Default: FALSE if global forwarding is disabled (default), ?? otherwise TRUE. ??hop_limit - INTEGER ?? Default Hop Limit to set. ?? Default: 64 ??mtu - INTEGER ?? Default Maximum Transfer Unit ?? Default: 1280 (IPv6 required minimum) ??router_solicitation_delay - INTEGER ?? Number of seconds to wait after interface is brought up ?? before sending Router Solicitations. ?? Default: 1 ??router_solicitation_interval - INTEGER ?? Number of seconds to wait between Router Solicitations. ?? Default: 4 ??router_solicitations - INTEGER ?? Number of Router Solicitations to send until assuming no ?? routers are present. ?? Default: 3 ??use_tempaddr - INTEGER ?? Preference for Privacy Extensions (RFC3041). ?? <= 0 : disable Privacy Extensions ?? == 1 : enable Privacy Extensions, but prefer public ?? addresses over temporary addresses. ?? > 1 : enable Privacy Extensions and prefer temporary ?? addresses over public addresses. ?? Default: 0 (for most devices) ?? -1 (for point-to-point devices and loopback devices) ??temp_valid_lft - INTEGER ?? valid lifetime (in seconds) for temporary addresses. ?? Default: 604800 (7 days) ??temp_prefered_lft - INTEGER ?? Preferred lifetime (in seconds) for temporary addresses. ?? Default: 86400 (1 day) ??max_desync_factor - INTEGER ?? Maximum value for DESYNC_FACTOR, which is a random value ?? that ensures that clients don't synchronize with each ?? other and generate new addresses at exactly the same time. ?? value is in seconds. ?? Default: 600 ??regen_max_retry - INTEGER ?? Number of attempts before give up attempting to generate ?? valid temporary addresses. ?? Default: 5 ??max_addresses - INTEGER ?? Number of maximum addresses per interface. 0 disables limitation. ?? It is recommended not set too large value (or 0) because it would ?? be too easy way to crash kernel to allow to create too much of ?? autoconfigured addresses. ?? Default: 16 ??icmp/*: ??ratelimit - INTEGER ?? Limit the maximal rates for sending ICMPv6 packets. ?? 0 to disable any limiting, otherwise the maximal rate in jiffies(1) ?? Default: 100 ?? ??IPv6 Update by: ??Pekka Savola ??YOSHIFUJI Hideaki / USAGI Project ??/proc/sys/net/bridge/* Variables: ??bridge-nf-call-arptables - BOOLEAN ?? 1 : pass bridged ARP traffic to arptables' FORWARD chain. ?? 0 : disable this. ?? Default: 1 ??bridge-nf-call-iptables - BOOLEAN ?? 1 : pass bridged IPv4 traffic to iptables' chains. ?? 0 : disable this. ?? Default: 1 ??bridge-nf-call-ip6tables - BOOLEAN ?? 1 : pass bridged IPv6 traffic to ip6tables' chains. ?? 0 : disable this. ?? Default: 1 ??bridge-nf-filter-vlan-tagged - BOOLEAN ?? 1 : pass bridged vlan-tagged ARP/IP traffic to arptables/iptables. ?? 0 : disable this. ?? Default: 1 ??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
