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有哪些关于 sysctl.conf 设置的建议可以增强 Linux 抵御 DDoS 攻击的能力？

tag-icon • tag-icon linux ddos hardening
有哪些关于 sysctl.conf 设置的建议可以增强 Linux 抵御 DDoS 攻击的能力？

UNIXy 最近发表的一篇文章http://blog.unixy.net/2010/08/the-penultimate-guide-to-stopping-a-ddos-attack-a-new-approach/提出了一些建议来增强 Linux 系统抵御 DDoS 攻击的能力。

示例sysctl.conf

net.ipv4.tcp_syncookies = 1

net.ipv4.conf.all.rp_filter = 1

net.ipv4.conf.default.rp_filter = 1

kernel.pid_max = 65536

net.ipv4.ip_local_port_range = 9000 65000

还有其他增强 Linux 抵御 DDoS 攻击的建议吗？

答案1

您还可以关闭读/写套接字缓冲区，这将减少每个入站连接所需的内存量。

http://wwwx.cs.unc.edu/~sparkst/howto/network_tuning.php

您必须对您的应用程序和硬件进行实际测试（是的，这些设置可能会根据您的 NIC 导致奇怪的副作用），因为根据您的流量，您可能会破坏比您节省的更多的东西。

答案2

您也可以设置以下内容。

# Turn on SYN-flood protections.  Starting with 2.6.26, there is no loss
# of TCP functionality/features under normal conditions.  When flood
# protections kick in under high unanswered-SYN load, the system
# should remain more stable, with a trade off of some loss of TCP
# functionality/features (e.g. TCP Window scaling).
net.ipv4.tcp_syncookies=1

# Ignore source-routed packets
net.ipv4.conf.all.accept_source_route=0
net.ipv4.conf.default.accept_source_route=0

# Ignore ICMP redirects from non-GW hosts
net.ipv4.conf.all.accept_redirects=0
net.ipv4.conf.default.accept_redirects=0
net.ipv4.conf.all.secure_redirects=1
net.ipv4.conf.default.secure_redirects=1

# Don't pass traffic between networks or act as a router
net.ipv4.ip_forward=0
net.ipv4.conf.all.send_redirects=0
net.ipv4.conf.default.send_redirects=0

# Turn on Source Address Verification in all interfaces to
# prevent some spoofing attacks.
net.ipv4.conf.all.rp_filter=1
net.ipv4.conf.default.rp_filter=1

# Ignore ICMP broadcasts to avoid participating in Smurf attacks
net.ipv4.icmp_echo_ignore_broadcasts=1

# Ignore bad ICMP errors
net.ipv4.icmp_ignore_bogus_error_responses=1

# Log spoofed, source-routed, and redirect packets
net.ipv4.conf.all.log_martians=1
net.ipv4.conf.default.log_martians=1

# RFC 1337 fix
net.ipv4.tcp_rfc1337=1

# Addresses of mmap base, heap, stack and VDSO page are randomized
kernel.randomize_va_space=2

# Reboot the machine soon after a kernel panic.
kernel.panic=10

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