##未初始化的TCP参数########
net.ipv4.tcp_abort_on_overflow = 0
net.ipv4.tcp_adv_win_scale = 1
net.ipv4.tcp_allowed_congestion_control = cubic reno
net.ipv4.tcp_app_win = 31
net.ipv4.tcp_autocorking = 1
net.ipv4.tcp_available_congestion_control = cubic reno
net.ipv4.tcp_base_mss = 512
net.ipv4.tcp_challenge_ack_limit = 1000
net.ipv4.tcp_congestion_control = cubic
net.ipv4.tcp_dsack = 1
net.ipv4.tcp_early_retrans = 3
net.ipv4.tcp_ecn = 2
net.ipv4.tcp_fack = 1
net.ipv4.tcp_fastopen = 0
net.ipv4.tcp_fastopen_key = 00000000-00000000-00000000-00000000
net.ipv4.tcp_fin_timeout = 60 #FIN包 60seconds超时
tcp_fin_timeout (integer; default: 60; since Linux 2.2)
This specifies how many seconds to wait for a final FIN packet before the socket is forcibly closed. This is strictly a violation of the TCP specification, but required
to prevent denial-of-service attacks. In Linux 2.2, the default value was 180.
net.ipv4.tcp_frto = 2
net.ipv4.tcp_invalid_ratelimit = 500
net.ipv4.tcp_keepalive_intvl = 75
net.ipv4.tcp_keepalive_probes = 9 # intvl * probes = 675 seconds 约 11分钟
net.ipv4.tcp_keepalive_time = 7200 #修改为600（10min）
tcp_keepalive_time (integer; default: 7200; since Linux 2.2)
The number of seconds a connection needs to be idle before TCP begins sending out keep-alive probes. Keep-alives are sent only when the SO_KEEPALIVE socket option is
enabled. The default value is 7200 seconds (2 hours). An idle connection is terminated after approximately an additional 11 minutes (9 probes an interval of 75 seconds
apart) when keep-alive is enabled.
net.ipv4.tcp_limit_output_bytes = 262144
net.ipv4.tcp_low_latency = 0
net.ipv4.tcp_max_orphans = 2048
net.ipv4.tcp_max_ssthresh = 0
net.ipv4.tcp_max_syn_backlog = 128 #修改为8192 个 syn队列缓存请求的数据包
tcp_max_syn_backlog (integer; default: see below; since Linux 2.2)
The maximum number of queued connection requests which have still not received an acknowledgement from the connecting client. If this number is exceeded, the kernel will
begin dropping requests. The default value of 256 is increased to 1024 when the memory present in the system is adequate or greater (>= 128Mb), and reduced to 128 for
those systems with very low memory (<= 32Mb). It is recommended that if this needs to be increased above 1024, TCP_SYNQ_HSIZE in include/net/tcp.h be modified to keep
TCP_SYNQ_HSIZE*16<=tcp_max_syn_backlog, and the kernel be recompiled.
net.ipv4.tcp_max_tw_buckets = 2048 # 允许time-wait数量
tcp_max_tw_buckets (integer; default: see below; since Linux 2.4)
The maximum number of sockets in TIME_WAIT state allowed in the system. This limit exists only to prevent simple denial-of-service attacks. The default value of
NR_FILE*2 is adjusted depending on the memory in the system. If this number is exceeded, the socket is closed and a warning is printed.
net.ipv4.tcp_mem = 11490 15323 22980
net.ipv4.tcp_min_tso_segs = 2
net.ipv4.tcp_moderate_rcvbuf = 1
net.ipv4.tcp_mtu_probing = 0
net.ipv4.tcp_no_metrics_save = 0
net.ipv4.tcp_notsent_lowat = -1
net.ipv4.tcp_orphan_retries = 0
net.ipv4.tcp_reordering = 3
net.ipv4.tcp_retrans_collapse = 1
net.ipv4.tcp_retries1 = 3
net.ipv4.tcp_retries2 = 15
net.ipv4.tcp_rfc1337 = 0
net.ipv4.tcp_rmem = 4096 87380 3793440
net.ipv4.tcp_sack = 1
net.ipv4.tcp_slow_start_after_idle = 1
net.ipv4.tcp_stdurg = 0
net.ipv4.tcp_syn_retries = 6
tcp_syn_retries (integer; default: 5; since Linux 2.2)
The maximum number of times initial SYNs for an active TCP connection attempt will be retransmitted. This value should not be higher than 255. The default value is 5,
which corresponds to approximately 180 seconds.
net.ipv4.tcp_synack_retries = 5
tcp_synack_retries (integer; default: 5; since Linux 2.2)
The maximum number of times a SYN/ACK segment for a passive TCP connection will be retransmitted. This number should not be higher than 255.
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_thin_dupack = 0
net.ipv4.tcp_thin_linear_timeouts = 0
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_tso_win_divisor = 3
net.ipv4.tcp_tw_recycle = 0
tcp_tw_recycle (Boolean; default: disabled; since Linux 2.4)
Enable fast recycling of TIME_WAIT sockets. Enabling this option is not recommended since this causes problems when working with NAT (Network Address Translation).
net.ipv4.tcp_tw_reuse = 0 #修改为1 time-wait进行重用
tcp_tw_reuse (Boolean; default: disabled; since Linux 2.4.19/2.6)
Allow to reuse TIME_WAIT sockets for new connections when it is safe from protocol viewpoint. It should not be changed without advice/request of technical experts.
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_wmem = 4096 16384 3793440
tcp_wmem (since Linux 2.4)
This is a vector of 3 integers: [min, default, max]. These parameters are used by TCP to regulate send buffer sizes. TCP dynamically adjusts the size of the send buffer
from the default values listed below, in the range of these values, depending on memory available.
min Minimum size of the send buffer used by each TCP socket. The default value is the system page size. (On Linux 2.4, the default value is 4K bytes.) This value
is used to ensure that in memory pressure mode, allocations below this size will still succeed. This is not used to bound the size of the send buffer declared
using SO_SNDBUF on a socket.
default The default size of the send buffer for a TCP socket. This value overwrites the initial default buffer size from the generic global
/proc/sys/net/core/wmem_default defined for all protocols. The default value is 16K bytes. If larger send buffer sizes are desired, this value should be
increased (to affect all sockets). To employ large TCP windows, the /proc/sys/net/ipv4/tcp_window_scaling must be set to a nonzero value (default).
max The maximum size of the send buffer used by each TCP socket. This value does not override the value in /proc/sys/net/core/wmem_max. This is not used to limit
the size of the send buffer declared using SO_SNDBUF on a socket. The default value is calculated using the formula
max(65536, min(4MB, tcp_mem[1]*PAGE_SIZE/128))
(On Linux 2.4, the default value is 128K bytes, lowered 64K depending on low-memory systems.)
net.ipv4.tcp_workaround_signed_windows = 0