# Protection from SYN flood attack.
net.ipv4.tcp_syncookies = 1
# See evil packets in your logs.
net.ipv4.conf.all.log_martians = 1
# Discourage Linux from swapping idle server processes to disk (default = 60)
vm.swappiness = 10
# Be less aggressive about reclaiming cached directory and inode objects
# in order to improve filesystem performance.
vm.vfs_cache_pressure = 50
# --------------------------------------------------------------------
# The following allow the server to handle lots of connection requests
# --------------------------------------------------------------------
# Increase number of incoming connections that can queue up
# before dropping
net.core.somaxconn = 50000
# Handle SYN floods and large numbers of valid HTTPS connections
net.ipv4.tcp_max_syn_backlog = 30000
# Increase the length of the network device input queue
net.core.netdev_max_backlog = 5000
# Increase system file descriptor limit so we will (probably)
# never run out under lots of concurrent requests.
# (Per-process limit is set in /etc/security/limits.conf)
fs.file-max = 100000
# Widen the port range used for outgoing connections
net.ipv4.ip_local_port_range = 10000 65000
# If your servers talk UDP, also up these limits
net.ipv4.udp_rmem_min = 8192
net.ipv4.udp_wmem_min = 8192
# --------------------------------------------------------------------
# The following help the server efficiently pipe large amounts of data
# --------------------------------------------------------------------
# Disable source routing and redirects
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.all.accept_source_route = 0
# Disable packet forwarding.
net.ipv4.ip_forward = 0
net.ipv6.conf.all.forwarding = 0
# Disable TCP slow start on idle connections
net.ipv4.tcp_slow_start_after_idle = 0
# Increase Linux autotuning TCP buffer limits
# Set max to 16MB for 1GE and 32M (33554432) or 54M (56623104) for 10GE
# Don't set tcp_mem itself! Let the kernel scale it based on RAM.
# net.core.rmem_max = 16777216
# net.core.wmem_max = 16777216
# net.core.rmem_default = 16777216
# net.core.wmem_default = 16777216
# net.core.optmem_max = 40960
# net.ipv4.tcp_rmem = 4096 87380 16777216
# net.ipv4.tcp_wmem = 4096 65536 16777216
# --------------------------------------------------------------------
# The following allow the server to handle lots of connection churn
# --------------------------------------------------------------------
# Disconnect dead TCP connections after 1 minute
net.ipv4.tcp_keepalive_time = 60
# Wait a maximum of 5 * 2 = 10 seconds in the TIME_WAIT state after a FIN, to handle
# any remaining packets in the network.
# net.ipv4.netfilter.ip_conntrack_tcp_timeout_time_wait = 5
# Allow a high number of timewait sockets
net.ipv4.tcp_max_tw_buckets = 2000000
# Timeout broken connections faster (amount of time to wait for FIN)
net.ipv4.tcp_fin_timeout = 10
# Let the networking stack reuse TIME_WAIT connections when it thinks it's safe to do so
net.ipv4.tcp_tw_reuse = 1
# Determines the wait time between isAlive interval probes (reduce from 75 sec to 15)
net.ipv4.tcp_keepalive_intvl = 15
# Determines the number of probes before timing out (reduce from 9 sec to 5 sec)
net.ipv4.tcp_keepalive_probes = 5
vi /etc/security/limits.conf
httpd soft nofile 55536
httpd hard nofile 55536
nginx soft nofile 55536
nginx hard nofile 55536
lesstif soft nofile 55536
lesstif hard nofile 55536