76 lines
3.2 KiB
Nix
76 lines
3.2 KiB
Nix
{
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# this is a collection of tcp related sysctl commands that are floating around,
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# unsure who the original author is
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# see:
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# <https://madaidans-insecurities.github.io/guides/linux-hardening.html>
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# github:fort-nix/nix-bitcoin
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# github:hlissner/dotfiles
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# github:notashelf/nyx
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boot = {
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kernel.sysctl = {
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# TCP hardening
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# Prevent bogus ICMP errors from filling up logs.
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"net.ipv4.icmp_ignore_bogus_error_responses" = 1;
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# Reverse path filtering causes the kernel to do source validation of
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# packets received from all interfaces. This can mitigate IP spoofing.
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"net.ipv4.conf.default.rp_filter" = 1;
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"net.ipv4.conf.all.rp_filter" = 1;
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# Do not accept IP source route packets (we're not a router)
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"net.ipv4.conf.all.accept_source_route" = 0;
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"net.ipv6.conf.all.accept_source_route" = 0;
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# Don't send ICMP redirects (again, we're on a router)
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"net.ipv4.conf.all.send_redirects" = 0;
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"net.ipv4.conf.default.send_redirects" = 0;
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# Refuse ICMP redirects (MITM mitigations)
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"net.ipv4.conf.all.accept_redirects" = 0;
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"net.ipv4.conf.default.accept_redirects" = 0;
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"net.ipv4.conf.all.secure_redirects" = 0;
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"net.ipv4.conf.default.secure_redirects" = 0;
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"net.ipv6.conf.all.accept_redirects" = 0;
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"net.ipv6.conf.default.accept_redirects" = 0;
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# Protects against SYN flood attacks
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"net.ipv4.tcp_syncookies" = 1;
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# Incomplete protection again TIME-WAIT assassination
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"net.ipv4.tcp_rfc1337" = 1;
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# And other stuff
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"net.ipv4.conf.all.log_martians" = true;
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"net.ipv4.conf.default.log_martians" = true;
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"net.ipv4.icmp_echo_ignore_broadcasts" = true;
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"net.ipv6.conf.default.accept_ra" = 0;
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"net.ipv6.conf.all.accept_ra" = 0;
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"net.ipv4.tcp_timestamps" = 0;
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# TCP optimization
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# TCP Fast Open is a TCP extension that reduces network latency by packing
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# data in the sender’s initial TCP SYN. Setting 3 = enable TCP Fast Open for
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# both incoming and outgoing connections:
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"net.ipv4.tcp_fastopen" = 3;
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# Bufferbloat mitigations + slight improvement in throughput & latency
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"net.ipv4.tcp_congestion_control" = "bbr";
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"net.core.default_qdisc" = "cake";
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# Other stuff that I am too lazy to document
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"net.core.optmem_max" = 65536;
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"net.core.rmem_default" = 1048576;
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"net.core.rmem_max" = 16777216;
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"net.core.somaxconn" = 8192;
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"net.core.wmem_default" = 1048576;
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"net.core.wmem_max" = 16777216;
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"net.ipv4.ip_local_port_range" = "16384 65535";
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"net.ipv4.tcp_max_syn_backlog" = 8192;
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"net.ipv4.tcp_max_tw_buckets" = 2000000;
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"net.ipv4.tcp_mtu_probing" = 1;
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"net.ipv4.tcp_rmem" = "4096 1048576 2097152";
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"net.ipv4.tcp_slow_start_after_idle" = 0;
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"net.ipv4.tcp_tw_reuse" = 1;
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"net.ipv4.tcp_wmem" = "4096 65536 16777216";
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"net.ipv4.udp_rmem_min" = 8192;
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"net.ipv4.udp_wmem_min" = 8192;
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"net.netfilter.nf_conntrack_generic_timeout" = 60;
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"net.netfilter.nf_conntrack_max" = 1048576;
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"net.netfilter.nf_conntrack_tcp_timeout_established" = 600;
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"net.netfilter.nf_conntrack_tcp_timeout_time_wait" = 1;
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};
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};
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}
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