1 net.ipv4.ip_forward = 1
2 net.ipv4.ip_dynaddr = 1
4 net.ipv4.icmp_echo_ignore_broadcasts = 1
5 net.ipv4.icmp_ignore_bogus_error_responses = 1
6 net.ipv4.icmp_ratelimit = 1000
7 net.ipv4.icmp_ratemask = 6168
9 net.ipv4.tcp_syncookies = 1
10 net.ipv4.tcp_fin_timeout = 30
11 net.ipv4.tcp_syn_retries = 3
12 net.ipv4.tcp_synack_retries = 3
14 net.ipv4.conf.default.arp_filter = 1
15 net.ipv4.conf.default.rp_filter = 1
16 net.ipv4.conf.default.accept_redirects = 0
17 net.ipv4.conf.default.accept_source_route = 0
18 net.ipv4.conf.default.log_martians = 1
20 net.ipv4.conf.all.arp_filter = 1
21 net.ipv4.conf.all.rp_filter = 1
22 net.ipv4.conf.all.accept_redirects = 0
23 net.ipv4.conf.all.accept_source_route = 0
24 net.ipv4.conf.all.log_martians = 1
26 kernel.printk = 1 4 1 7
27 vm.mmap_min_addr = 4096
28 vm.min_free_kbytes = 8192
30 # Disable IPv6 by default.
31 net.ipv6.conf.all.disable_ipv6 = 1
32 net.ipv6.conf.default.disable_ipv6 = 1
34 # Enable netfilter accounting
35 net.netfilter.nf_conntrack_acct = 1
37 # Disable netfilter on bridges.
38 net.bridge.bridge-nf-call-ip6tables = 0
39 net.bridge.bridge-nf-call-iptables = 0
40 net.bridge.bridge-nf-call-arptables = 0
42 # Restrict loading TTY line disciplines to CAP_SYS_MODULE to prevent unprivileged attackers
43 # from loading vulnerable line disciplines with the TIOCSETD ioctl.
44 dev.tty.ldisc_autoload = 0
46 # Try to keep kernel address exposures out of various /proc files (kallsyms, modules, etc).
47 kernel.kptr_restrict = 2
49 # Avoid kernel memory address exposures via dmesg.
50 kernel.dmesg_restrict = 1
52 # Turn on hard- and symlink protection
53 fs.protected_symlinks = 1
54 fs.protected_hardlinks = 1
56 # Don't allow writes to files and FIFOs that we don't own in world writable sticky
57 # directories, unless they are owned by the owner of the directory.
58 fs.protected_fifos = 2
59 fs.protected_regular = 2
61 # If a workload mostly uses anonymous memory and it hits this limit, the entire
62 # working set is buffered for I/O, and any more write buffering would require
63 # swapping, so it's time to throttle writes until I/O can catch up. Workloads
64 # that mostly use file mappings may be able to use even higher values.
66 # The generator of dirty data starts writeback at this percentage (system default
70 # Start background writeback (via writeback threads) at this percentage (system
72 vm.dirty_background_ratio = 3
74 # The swappiness parameter controls the tendency of the kernel to move
75 # processes out of physical memory and onto the swap disk.
76 # 0 tells the kernel to avoid swapping processes out of physical memory
77 # for as long as possible
78 # 100 tells the kernel to aggressively swap processes out of physical memory
79 # and move them to swap cache
82 # Increase kernel buffer size maximums
83 net.ipv4.tcp_mem = 16777216 16777216 16777216
84 net.ipv4.tcp_rmem = 4096 87380 16777216
85 net.ipv4.tcp_wmem = 4096 16384 16777216
86 net.ipv4.udp_mem = 3145728 4194304 16777216
88 # Prefer low latency over higher throughput
89 net.ipv4.tcp_low_latency = 1
91 # Reserve more socket space for the TCP window
92 net.ipv4.tcp_adv_win_scale = 2
94 # Enable TCP fast-open
95 net.ipv4.tcp_fastopen = 3
97 # Drop RST packets for sockets in TIME-WAIT state, as described in RFC 1337.
98 # This protects against various TCP attacks, such as DoS against or injection
99 # of arbitrary segments into prematurely closed connections.
100 net.ipv4.tcp_rfc1337 = 1
102 # Include PID in file names of generated core dumps
103 kernel.core_uses_pid = 1
105 # Block non-uid-0 profiling
106 kernel.perf_event_paranoid = 3