65 lines
2.3 KiB
Nix
65 lines
2.3 KiB
Nix
# security tweaks borrowed from @hlissner
|
||
{
|
||
boot.kernel.sysctl = {
|
||
# The Magic SysRq key is a key combo that allows users connected to the
|
||
# system console of a Linux kernel to perform some low-level commands.
|
||
# Disable it, since we don't need it, and is a potential security concern.
|
||
"kernel.sysrq" = 0;
|
||
|
||
## TCP hardening
|
||
# Prevent bogus ICMP errors from filling up logs.
|
||
"net.ipv4.icmp_ignore_bogus_error_responses" = 1;
|
||
# Reverse path filtering causes the kernel to do source validation of
|
||
# packets received from all interfaces. This can mitigate IP spoofing.
|
||
"net.ipv4.conf.default.rp_filter" = 1;
|
||
"net.ipv4.conf.all.rp_filter" = 1;
|
||
# Do not accept IP source route packets (we're not a router)
|
||
"net.ipv4.conf.all.accept_source_route" = 0;
|
||
"net.ipv6.conf.all.accept_source_route" = 0;
|
||
# Don't send ICMP redirects (again, we're on a router)
|
||
"net.ipv4.conf.all.send_redirects" = 0;
|
||
"net.ipv4.conf.default.send_redirects" = 0;
|
||
# Refuse ICMP redirects (MITM mitigations)
|
||
"net.ipv4.conf.all.accept_redirects" = 0;
|
||
"net.ipv4.conf.default.accept_redirects" = 0;
|
||
"net.ipv4.conf.all.secure_redirects" = 0;
|
||
"net.ipv4.conf.default.secure_redirects" = 0;
|
||
"net.ipv6.conf.all.accept_redirects" = 0;
|
||
"net.ipv6.conf.default.accept_redirects" = 0;
|
||
# Protects against SYN flood attacks
|
||
"net.ipv4.tcp_syncookies" = 1;
|
||
# Incomplete protection again TIME-WAIT assassination
|
||
"net.ipv4.tcp_rfc1337" = 1;
|
||
|
||
## TCP optimization
|
||
# TCP Fast Open is a TCP extension that reduces network latency by packing
|
||
# data in the sender’s initial TCP SYN. Setting 3 = enable TCP Fast Open for
|
||
# both incoming and outgoing connections:
|
||
"net.ipv4.tcp_fastopen" = 3;
|
||
# Bufferbloat mitigations + slight improvement in throughput & latency
|
||
"net.ipv4.tcp_congestion_control" = "bbr";
|
||
"net.core.default_qdisc" = "cake";
|
||
};
|
||
boot.kernelModules = ["tcp_bbr"];
|
||
|
||
# So we don't have to do this later...
|
||
security.acme = {
|
||
acceptTerms = true;
|
||
defaults.email = "github@notohh.dev";
|
||
};
|
||
services.fail2ban = {
|
||
enable = true;
|
||
ignoreIP = [
|
||
"192.168.0.0/16"
|
||
"172.16.0.0/12"
|
||
"10.0.0.0/8"
|
||
"5.161.181.184"
|
||
];
|
||
extraSettings = {
|
||
findtime = 100000;
|
||
bantime = 100000;
|
||
maxretry = 1;
|
||
mode = "aggressive";
|
||
};
|
||
};
|
||
}
|