edit /etc/sysctl.d/60-zercle.conf
and run
sysctl --system
| # Kernel sysctl configuration file for Linux | |
| # https://www.kernel.org/doc/Documentation/sysctl/ | |
| # | |
| # Original by Michiel Klaver <https://klaver.it/linux/sysctl.conf> | |
| # Modify by Kawin Viriyaprasopsook <[email protected]> | |
| # | |
| # The following is suitable for dedicated web server, mail, file server, KVM server etc. | |
| # place file in /etc/sysctl.d/60-sysctl.conf | |
| # and run sysctl –system | |
| # ——————————————————————– | |
| # System options | |
| # ——————————————————————– | |
| # Controls IP packet forwarding (Default 0 but docker,vpn,router server must set to 1) | |
| net.ipv4.ip_forward = 0 | |
| net.ipv6.conf.all.forwarding = 0 | |
| # Addresses of mmap base, heap, stack and VDSO page are randomized | |
| kernel.randomize_va_space = 2 | |
| # Controls the System Request debugging functionality of the kernel | |
| kernel.sysrq = 0 | |
| # Controls whether core dumps will append the PID to the core filename. | |
| # Useful for debugging multi-threaded applications. | |
| kernel.core_uses_pid = 1 | |
| # Allow for more PIDs | |
| kernel.pid_max = 65535 | |
| # Changing Semaphore Limits | |
| kernel.msgmni = 1024 | |
| kernel.sem = 250 256000 32 1024 | |
| # Controls the default maxmimum size of a mesage queue | |
| kernel.msgmnb = 65535 | |
| # Controls the maximum size of a message, in bytes | |
| kernel.msgmax = 65535 | |
| # Controls the maximum number of shared memory segments, in pages | |
| kernel.shmall = 268435456 | |
| # Controls the maximum shared segment size, in bytes | |
| kernel.shmmax = 268435456 | |
| # Keep at least 64MB of free RAM space available | |
| vm.min_free_kbytes = 65535 | |
| # Controls source route verification | |
| net.ipv4.conf.all.rp_filter = 2 | |
| net.ipv4.conf.default.rp_filter = 2 | |
| # Do not accept source routing | |
| net.ipv4.conf.default.accept_source_route = 0 | |
| net.ipv6.conf.default.accept_source_route = 0 | |
| # Disable ICMP Redirect Acceptance | |
| 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 | |
| # Disable netfilter on bridges. | |
| net.bridge.bridge-nf-call-ip6tables = 0 | |
| net.bridge.bridge-nf-call-iptables = 0 | |
| net.bridge.bridge-nf-call-arptables = 0 | |
| # Discourage Linux from swapping idle server processes to disk (default = 60) | |
| vm.swappiness = 10 | |
| vm.dirty_ratio = 60 | |
| vm.dirty_background_ratio = 2 | |
| # RFC 1337 fix | |
| net.ipv4.tcp_rfc1337 = 1 | |
| # Tweak how the flow of kernel messages is throttled. | |
| #kernel.printk_ratelimit_burst = 10 | |
| #kernel.printk_ratelimit = 5 | |
| # ——————————————————————– | |
| # The following allow the server to handle lots of connection requests | |
| # ——————————————————————– | |
| # See also http://www.nateware.com/linux-network-tuning-for-2013.html for | |
| # an explanation about some of these parameters, and instructions for | |
| # a few other tweaks outside this file. | |
| # Protection from SYN flood attack. | |
| net.ipv4.tcp_syncookies = 1 | |
| net.ipv4.tcp_syn_retries = 2 | |
| net.ipv4.tcp_synack_retries = 2 | |
| # Increase number of incoming connections that can queue up | |
| # before dropping | |
| net.core.somaxconn = 32768 | |
| # Handle SYN floods and large numbers of valid HTTPS connections | |
| # https://shehab.tech/ | |
| net.ipv4.tcp_max_syn_backlog = 4096 | |
| # Increase the length of the network device input queue | |
| net.core.netdev_max_backlog = 16384 | |
| # Increase system file descriptor limit so we will (probably) | |
| # never run out under lots of concurrent requests. | |
| # (Per-process limit is set in /etc/security/limits.conf) | |
| fs.file-max = 209708 | |
| # Widen the port range used for outgoing connections | |
| net.ipv4.ip_local_port_range = 1024 65535 | |
| # Increasing the amount of inotify watchers | |
| fs.inotify.max_user_watches = 524288 | |
| # ——————————————————————– | |
| # The following help the server efficiently pipe large amounts of data | |
| # ——————————————————————– | |
| # Disable source routing and redirects | |
| net.ipv4.conf.all.send_redirects = 0 | |
| net.ipv4.conf.default.send_redirects = 0 | |
| net.ipv4.conf.all.accept_source_route = 0 | |
| net.ipv4.conf.default.accept_source_route = 0 | |
| net.ipv6.conf.all.accept_source_route = 0 | |
| net.ipv6.conf.default.accept_source_route = 0 | |
| # Avoid falling back to slow start after a connection goes idle | |
| # keeps our cwnd large with the keep alive connections (kernel > 3.6) | |
| net.ipv4.tcp_slow_start_after_idle = 0 | |
| # Controls TCP Packetization-Layer Path MTU Discovery | |
| net.ipv4.tcp_mtu_probing = 1 | |
| # Turn on the tcp_window_scaling | |
| net.ipv4.tcp_window_scaling = 1 | |
| # Turn on the tcp_timestamps, accurate timestamp make TCP congestion control algorithms work better | |
| net.ipv4.tcp_timestamps = 1 | |
| # Enable the TCP selective acks option for better throughput | |
| net.ipv4.tcp_sack = 1 | |
| # Change Congestion Control | |
| # Use BBR TCP congestion control and set tcp_notsent_lowat to 16384 to ensure HTTP/2 prioritization works optimally | |
| # Do a 'modprobe tcp_bbr' first (kernel > 4.9) | |
| # Fall-back to htcp if bbr is unavailable (older kernels) | |
| net.ipv4.tcp_congestion_control = htcp | |
| net.ipv4.tcp_congestion_control = bbr | |
| net.core.default_qdisc = fq | |
| # bbr + fq_codel for kernel >= 4.13 | |
| #net.core.default_qdisc = fq_codel | |
| net.ipv4.tcp_notsent_lowat = 16384 | |
| # Increase the maximum amount of option memory buffers | |
| net.core.optmem_max = 65535 | |
| # Increase Linux autotuning TCP buffer limits | |
| # Set max to 16MB (16777216) for 1GE and 32M (33554432) or 54M (56623104) for 10GE | |
| # Don't set tcp_mem itself! Let the kernel scale it based on RAM. | |
| # Increase the read-buffer space allocatable | |
| net.ipv4.tcp_rmem = 8192 87380 33554432 | |
| net.ipv4.udp_rmem_min = 16384 | |
| net.core.rmem_default = 262144 | |
| net.core.rmem_max = 33554432 | |
| # Increase the write-buffer-space allocatable | |
| net.ipv4.tcp_wmem = 8192 65536 33554432 | |
| net.ipv4.udp_wmem_min = 16384 | |
| net.core.wmem_default = 262144 | |
| net.core.wmem_max = 33554432 | |
| # If your servers talk UDP, also up these limits | |
| net.ipv4.udp_rmem_min = 16384 | |
| net.ipv4.udp_wmem_min = 16384 | |
| # ——————————————————————– | |
| # The following allow the server to handle lots of connection churn | |
| # ——————————————————————– | |
| # Increase the tcp-time-wait buckets pool size to prevent simple DOS attacks | |
| net.ipv4.tcp_max_tw_buckets = 1440000 | |
| # Timeout broken connections faster (amount of time to wait for FIN) | |
| net.ipv4.tcp_fin_timeout = 7 | |
| # Try to reuse time-wait connections, but don't recycle them (recycle can break clients behind NAT) | |
| net.ipv4.tcp_tw_recycle = 0 | |
| net.ipv4.tcp_tw_reuse = 1 | |
| # Decrease the time default value for connections to keep alive | |
| # Disconnect dead TCP connections after 600+(60*10) seconds | |
| net.ipv4.tcp_keepalive_time = 600 | |
| net.ipv4.tcp_keepalive_probes = 60 | |
| net.ipv4.tcp_keepalive_intvl = 10 | |
| # This will enusre that immediatly subsequent connections use the new values | |
| net.ipv4.route.flush = 1 | |
| net.ipv6.route.flush = 1 |
/etc/iptables.up.rules
# Generated by iptables-save v1.6.0 on Thu Mar 30 00:19:26 2017 *raw :PREROUTING ACCEPT [1324:102679] :OUTPUT ACCEPT [110:12756] # Don't track SYN packets -A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CT --notrack COMMIT # Completed on Thu Mar 30 00:19:26 2017 *mangle :PREROUTING ACCEPT [1324:102679] :INPUT ACCEPT [1248:94938] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [110:12756] :POSTROUTING ACCEPT [110:12756] # Allow loopback -A PREROUTING -i lo -j ACCEPT # Drop TCP packets that are new and are not SYN -A PREROUTING -p tcp -m tcp ! --tcp-flags FIN,SYN,RST,ACK SYN -m conntrack --ctstate NEW -j DROP # Drop SYN packets with suspicious MSS value -A PREROUTING -p tcp -m conntrack --ctstate NEW -m tcpmss ! --mss 536:65535 -j DROP # Block packets with bogus TCP flags -A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN FIN,SYN -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags SYN,RST SYN,RST -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN FIN,SYN -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags FIN,RST FIN,RST -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags FIN,ACK FIN -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags ACK,URG URG -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags FIN,ACK FIN -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags PSH,ACK PSH -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG FIN,SYN,RST,PSH,ACK,URG -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG FIN,PSH,URG -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG FIN,SYN,PSH,URG -j DROP -A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG FIN,SYN,RST,ACK,URG -j DROP # Block spoofed packets -A PREROUTING -s 224.0.0.0/3 -j DROP -A PREROUTING -s 169.254.0.0/16 -j DROP -A PREROUTING -s 172.16.0.0/12 -j DROP -A PREROUTING -s 192.0.2.0/24 -j DROP -A PREROUTING -s 192.168.0.0/16 -j DROP -A PREROUTING -s 10.0.0.0/8 -j DROP -A PREROUTING -s 0.0.0.0/8 -j DROP -A PREROUTING -s 240.0.0.0/5 -j DROP -A PREROUTING -s 127.0.0.0/8 ! -i lo -j DROP # Drop fragments in all chains -A PREROUTING -f -j DROP COMMIT # Completed on Thu Mar 30 00:19:26 2017 # Generated by iptables-save v1.6.0 on Tue Mar 28 11:50:15 2017 *nat :INPUT ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] :PREROUTING ACCEPT [0:0] -A POSTROUTING -j MASQUERADE COMMIT # Completed on Thu Mar 30 00:19:26 2017 # Generated by iptables-save v1.6.0 on Tue Mar 28 11:50:15 2017 *filter :INPUT ACCEPT [1246:94823] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [110:12756] :port-scanning - [0:0] # Allow loopback -A INPUT -i lo -j ACCEPT # Allow current connection -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT #Limiting the incoming icmp ping request: -A INPUT -p icmp -m limit --limit 1/s --limit-burst 2 -j ACCEPT -A INPUT -p icmp -j DROP # Simple DDOS Migation by SYNPROXY -A INPUT -p tcp -m tcp -m conntrack --ctstate INVALID,UNTRACKED -j SYNPROXY --sack-perm --timestamp --wscale 7 --mss 1460 -m multiport --dports 22,80,443 -A INPUT -p tcp -m tcp -m conntrack --ctstate INVALID,UNTRACKED -j SYNPROXY --sack-perm --timestamp --wscale 7 --mss 1460 -m multiport --dports 8080,8443 -A INPUT -m conntrack --ctstate INVALID -j DROP # SSH brute-force protection -A INPUT -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW -m recent --set --name SSHBF --rsource -A INPUT -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW -m recent --update --seconds 60 --hitcount 10 --name SSHBF --rsource -j DROP # Protection against port scanning -A port-scanning -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK RST -m limit --limit 1/sec --limit-burst 2 -j RETURN -A port-scanning -j DROP # Allow Apps -A INPUT -p tcp -m tcp -m multiport -j ACCEPT --dports 22,80,443 -A INPUT -p tcp -m tcp -m multiport -j ACCEPT --dports 8080,8443 # Default DROP -A INPUT -j DROP COMMIT # Completed on Thu Mar 30 00:19:26 2017
/etc/ip6tables.up.rules
# Generated by iptables-save v1.6.0 on Thu Mar 30 00:19:26 2017 *raw :PREROUTING ACCEPT [1324:102679] :OUTPUT ACCEPT [110:12756] # Don't track SYN packets -A PREROUTING -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CT --notrack COMMIT # Completed on Thu Mar 30 00:19:26 2017 # Generated by iptables-save v1.6.0 on Tue Mar 28 11:50:15 2017 *filter :INPUT ACCEPT [1246:94823] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [110:12756] :port-scanning - [0:0] # Allow loopback -A INPUT -i lo -j ACCEPT # Allow current connection -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT -A FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT #Limiting the incoming icmp ping request: -A INPUT -p ipv6-icmp -m limit --limit 1/s --limit-burst 2 -j ACCEPT -A INPUT -p ipv6-icmp -j DROP # Simple DDOS Migation by SYNPROXY -A INPUT -p tcp -m tcp -m conntrack --ctstate INVALID,UNTRACKED -j SYNPROXY --sack-perm --timestamp --wscale 7 --mss 1460 -m multiport --dports 22,80,443 -A INPUT -p tcp -m tcp -m conntrack --ctstate INVALID,UNTRACKED -j SYNPROXY --sack-perm --timestamp --wscale 7 --mss 1460 -m multiport --dports 8080,8443 -A INPUT -m conntrack --ctstate INVALID -j DROP # SSH brute-force protection -A INPUT -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW -m recent --set --name SSHBF --rsource -A INPUT -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW -m recent --update --seconds 60 --hitcount 10 --name SSHBF --rsource -j DROP # Protection against port scanning -A port-scanning -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK RST -m limit --limit 1/sec --limit-burst 2 -j RETURN -A port-scanning -j DROP # Allow Apps -A INPUT -p tcp -m tcp -m multiport -j ACCEPT --dports 22,80,443 -A INPUT -p tcp -m tcp -m multiport -j ACCEPT --dports 8080,8443 # Default DROP -A INPUT -j DROP COMMIT # Completed on Thu Mar 30 00:19:26 2017 # Generated by iptables-save v1.6.0 on Tue Mar 28 11:50:15 2017 *mangle :PREROUTING ACCEPT [1324:102679] :INPUT ACCEPT [1248:94938] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [110:12756] :POSTROUTING ACCEPT [110:12756] COMMIT # Completed on Thu Mar 30 00:19:26 2017 # Generated by iptables-save v1.6.0 on Tue Mar 28 11:50:15 2017 *nat :INPUT ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] :PREROUTING ACCEPT [0:0] -A POSTROUTING -j MASQUERADE COMMIT # Completed on Thu Mar 30 00:19:26 2017
Debian,Ubuntu load iptables
/etc/network/if-pre-up.d/iptablesload
chmod +x /etc/network/if-pre-up.d/iptablesload
#!/usr/bin/env bash sysctl --system > /dev/null 2>&1 iptables-restore < /etc/iptables.up.rules ip6tables-restore < /etc/ip6tables.up.rules exit 0
RHEL,Centos load iptables
#!/usr/bin/env bash sysctl --system > /dev/null 2>&1 systemctl mask firewalld yum -y install iptables-services systemctl enable iptables systemctl enable ip6tables iptables-restore < /etc/iptables.up.rules ip6tables-restore < /etc/ip6tables.up.rules ln -sf /etc/iptables.up.rules /etc/sysconfig/iptables ln -sf /etc/ip6tables.up.rules /etc/sysconfig/ip6tables exit 0