diff options
Diffstat (limited to 'Documentation/networking/ip-sysctl.txt')
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 68 |
1 files changed, 59 insertions, 9 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 6f896b94abdc..ca447b35b833 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -48,12 +48,6 @@ 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 @@ -468,6 +462,19 @@ tcp_syncookies - BOOLEAN SYN flood warnings in logs not being really flooded, your server is seriously misconfigured. +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 not use connect(). Instead, it should use sendmsg() or sendto() + with MSG_FASTOPEN flag which performs a TCP handshake automatically. + + The values (bitmap) are: + 1: Enables sending data in the opening SYN on the client + 5: Enables sending data in the opening SYN on the client regardless + of cookie availability. + + 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 @@ -551,6 +558,25 @@ 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. + Note: For GSO/TSO enabled flows, we try to have at least two + packets in flight. Reducing tcp_limit_output_bytes might also + reduce the size of individual GSO packet (64KB being the max) + 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 @@ -857,9 +883,19 @@ 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 @@ -1398,6 +1434,20 @@ 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 |