graphene-os-server-infrastructure/sysctl.d/local.conf

net.ipv6.bindv6only = 1

net.ipv4.ip_local_port_range = 1024 65535

net.ipv4.conf.*.send_redirects = 0
net.ipv4.conf.*.accept_redirects = 0
net.ipv6.conf.*.accept_redirects = 0

# enforced with nftables to handle both IPv4 and IPv6 in the same way
net.ipv4.conf.default.rp_filter = 0
net.ipv4.conf.*.rp_filter = 0

net.ipv4.tcp_ecn = 1
net.ipv4.tcp_slow_start_after_idle = 0
net.ipv4.tcp_shrink_window = 1
net.ipv4.tcp_notsent_lowat = 131072
net.ipv4.tcp_fin_timeout = 30
net.ipv4.tcp_rfc1337 = 1
net.ipv4.tcp_tw_reuse = 1

# 31s with initial 1s RTO
net.ipv4.tcp_syn_retries = 4
net.netfilter.nf_conntrack_tcp_timeout_syn_sent = 31

# 15s with initial 1s RTO
net.ipv4.tcp_synack_retries = 3
net.netfilter.nf_conntrack_tcp_timeout_syn_recv = 15

# 102.2s with minimum 0.2s RTO
net.ipv4.tcp_retries2 = 8

# 25.4s with minimum 0.2s RTO
net.ipv4.tcp_orphan_retries = 6

net.mptcp.enabled = 0

net.netfilter.nf_conntrack_tcp_loose = 0
net.netfilter.nf_conntrack_tcp_timeout_established = 14400
net.netfilter.nf_conntrack_tcp_timeout_time_wait = 60
net.netfilter.nf_conntrack_udp_timeout = 15
net.netfilter.nf_conntrack_udp_timeout_stream = 15
net.netfilter.nf_conntrack_expect_max = 1

kernel.yama.ptrace_scope = 2

vm.mmap_rnd_bits = 32
vm.mmap_rnd_compat_bits = 16

kernel.kptr_restrict = 2

kernel.unprivileged_userns_clone = 0

kernel.unprivileged_bpf_disabled = 1
net.core.bpf_jit_harden = 2

kernel.io_uring_disabled = 1
kernel.io_uring_group = 2000

kernel.kexec_load_disabled = 1

fs.protected_regular = 2
fs.protected_fifos = 2

kernel.panic = -1
kernel.panic_on_oops = 1

dev.tty.ldisc_autoload = 0

fs.binfmt_misc.status = 0

kernel.sched_energy_aware = 0