diff options
Diffstat (limited to 'Documentation/networking/ip-sysctl.txt')
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 97 |
1 files changed, 86 insertions, 11 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 35ffaa281b26..32b21571adfe 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -26,7 +26,7 @@ ip_no_pmtu_disc - INTEGER 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 + Mode 3 is a hardened 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 @@ -81,6 +81,15 @@ fib_multipath_hash_policy - INTEGER 0 - Layer 3 1 - Layer 4 +ip_forward_update_priority - INTEGER + Whether to update SKB priority from "TOS" field in IPv4 header after it + is forwarded. The new SKB priority is mapped from TOS field value + according to an rt_tos2priority table (see e.g. man tc-prio). + Default: 1 (Update priority.) + Possible values: + 0 - Do not update priority. + 1 - Update priority. + route/max_size - INTEGER Maximum number of routes allowed in the kernel. Increase this when using large numbers of interfaces and/or routes. @@ -307,6 +316,17 @@ tcp_frto - INTEGER By default it's enabled with a non-zero value. 0 disables F-RTO. +tcp_fwmark_accept - BOOLEAN + If set, incoming connections to listening sockets that do not have a + socket mark will set the mark of the accepting socket to the fwmark of + the incoming SYN packet. This will cause all packets on that connection + (starting from the first SYNACK) to be sent with that fwmark. The + listening socket's mark is unchanged. Listening sockets that already + have a fwmark set via setsockopt(SOL_SOCKET, SO_MARK, ...) are + unaffected. + + Default: 0 + tcp_invalid_ratelimit - INTEGER Limit the maximal rate for sending duplicate acknowledgments in response to incoming TCP packets that are for an existing @@ -416,7 +436,7 @@ tcp_mtu_probing - INTEGER 1 - Disabled by default, enabled when an ICMP black hole detected 2 - Always enabled, use initial MSS of tcp_base_mss. -tcp_probe_interval - INTEGER +tcp_probe_interval - UNSIGNED INTEGER Controls how often to start TCP Packetization-Layer Path MTU Discovery reprobe. The default is reprobing every 10 minutes as per RFC4821. @@ -449,8 +469,10 @@ tcp_recovery - INTEGER features. RACK: 0x1 enables the RACK loss detection for fast detection of lost - retransmissions and tail drops. + retransmissions and tail drops. It also subsumes and disables + RFC6675 recovery for SACK connections. RACK: 0x2 makes RACK's reordering window static (min_rtt/4). + RACK: 0x4 disables RACK's DUPACK threshold heuristic Default: 0x1 @@ -523,6 +545,19 @@ tcp_rmem - vector of 3 INTEGERs: min, default, max tcp_sack - BOOLEAN Enable select acknowledgments (SACKS). +tcp_comp_sack_delay_ns - LONG INTEGER + TCP tries to reduce number of SACK sent, using a timer + based on 5% of SRTT, capped by this sysctl, in nano seconds. + The default is 1ms, based on TSO autosizing period. + + Default : 1,000,000 ns (1 ms) + +tcp_comp_sack_nr - INTEGER + Max numer of SACK that can be compressed. + Using 0 disables SACK compression. + + Detault : 44 + 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 @@ -652,11 +687,15 @@ tcp_tso_win_divisor - INTEGER building larger TSO frames. Default: 3 -tcp_tw_reuse - BOOLEAN - Allow to reuse TIME-WAIT sockets for new connections when it is - safe from protocol viewpoint. Default value is 0. +tcp_tw_reuse - INTEGER + Enable reuse of TIME-WAIT sockets for new connections when it is + safe from protocol viewpoint. + 0 - disable + 1 - global enable + 2 - enable for loopback traffic only It should not be changed without advice/request of technical experts. + Default: 2 tcp_window_scaling - BOOLEAN Enable window scaling as defined in RFC1323. @@ -714,11 +753,11 @@ 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. + result in a large amount of packets queued on the local machine + (e.g.: qdiscs, CPU backlog, or device) 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: 262144 tcp_challenge_ack_limit - INTEGER @@ -1414,6 +1453,14 @@ max_hbh_length - INTEGER header. Default: INT_MAX (unlimited) +skip_notify_on_dev_down - BOOLEAN + Controls whether an RTM_DELROUTE message is generated for routes + removed when a device is taken down or deleted. IPv4 does not + generate this message; IPv6 does by default. Setting this sysctl + to true skips the message, making IPv4 and IPv6 on par in relying + on userspace caches to track link events and evict routes. + Default: false (generate message) + IPv6 Fragmentation: ip6frag_high_thresh - INTEGER @@ -1428,6 +1475,19 @@ ip6frag_low_thresh - INTEGER ip6frag_time - INTEGER Time in seconds to keep an IPv6 fragment in memory. +IPv6 Segment Routing: + +seg6_flowlabel - INTEGER + Controls the behaviour of computing the flowlabel of outer + IPv6 header in case of SR T.encaps + + -1 set flowlabel to zero. + 0 copy flowlabel from Inner packet in case of Inner IPv6 + (Set flowlabel to 0 in case IPv4/L2) + 1 Compute the flowlabel using seg6_make_flowlabel() + + Default is 0. + conf/default/*: Change the interface-specific default settings. @@ -1802,6 +1862,16 @@ stable_secret - IPv6 address By default the stable secret is unset. +addr_gen_mode - INTEGER + Defines how link-local and autoconf addresses are generated. + + 0: generate address based on EUI64 (default) + 1: do no generate a link-local address, use EUI64 for addresses generated + from autoconf + 2: generate stable privacy addresses, using the secret from + stable_secret (RFC7217) + 3: generate stable privacy addresses, using a random secret if unset + drop_unicast_in_l2_multicast - BOOLEAN Drop any unicast IPv6 packets that are received in link-layer multicast (or broadcast) frames. @@ -1831,6 +1901,11 @@ ratelimit - INTEGER otherwise the minimal space between responses in milliseconds. Default: 1000 +echo_ignore_all - BOOLEAN + If set non-zero, then the kernel will ignore all ICMP ECHO + requests sent to it over the IPv6 protocol. + Default: 0 + xfrm6_gc_thresh - INTEGER The threshold at which we will start garbage collecting for IPv6 destination cache entries. At twice this value the system will |