sysctl.conf

# used on high bandwidth nodes

kernel.printk = 3 4 1 3
vm.swappiness=1
vm.min_free_kbytes = 8192

# TCP settings

# disabling forwarding first as this will
# reset some other values back to default (!)
net.ipv4.ip_forward = 0
net.ipv4.tcp_syncookies = 1
#net.ipv4.tcp_synack_retries = 2
#net.ipv4.tcp_syn_retries = 2
    
net.ipv4.conf.default.forwarding = 0 
net.ipv4.conf.default.proxy_arp = 0 
net.ipv4.conf.default.send_redirects = 1
net.ipv4.conf.all.rp_filter = 0
net.ipv4.conf.all.send_redirects = 0

kernel.sysrq = 1
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.icmp_ignore_bogus_error_responses = 1

# optimizations
net.core.rmem_max = 33554432
net.core.wmem_max = 33554432
net.ipv4.tcp_rmem = 4096 87380 33554432 
net.ipv4.tcp_wmem = 4096 65536 33554432  
net.core.netdev_max_backlog = 262144
net.ipv4.tcp_no_metrics_save = 1
net.ipv4.tcp_moderate_rcvbuf = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_max_orphans = 262144
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_fin_timeout = 4 
vm.min_free_kbytes = 65536
net.ipv4.netfilter.ip_conntrack_max = 196608
net.netfilter.nf_conntrack_tcp_timeout_established = 7200
net.netfilter.nf_conntrack_checksum = 0
net.netfilter.nf_conntrack_max = 196608 
net.netfilter.nf_conntrack_tcp_timeout_syn_sent = 15
net.nf_conntrack_max = 196608
net.ipv4.tcp_keepalive_time = 60
net.ipv4.tcp_keepalive_intvl = 10
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.ip_local_port_range = 1025 65530
net.core.somaxconn = 20480
net.ipv4.tcp_max_tw_buckets = 2000000
net.ipv4.tcp_timestamps = 0