在寻找更多保护 Linux 服务器的方法时，我发现了以下/etc/sysctl.conf配置。它就这样来了，没有太多解释。在生产环境（使用 Ubuntu 12.04 LTS）上使用它之前，我想知道它在 Web 服务器上的含义。
# Avoid a smurf attack
net.ipv4.icmp_echo_ignore_broadcasts = 1
# Turn on protection for bad icmp error messages
net.ipv4.icmp_ignore_bogus_error_responses = 1
# Turn on syncookies for SYN flood attack protection
net.ipv4.tcp_syncookies = 1
# Turn on and log spoofed, source routed, and redirect packets
net.ipv4.conf.all.log_martians = 1
net.ipv4.conf.default.log_martians = 1
# No source routed packets here
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0
# Turn on reverse path filtering
net.ipv4.conf.all.rp_filter = 1 …