最近，我的服务器遭受了来自中国防火墙的 DDoS 攻击。
根据其中一条回复中的建议mod_security 通过 http-host 标头阻止请求以及https://mattwilcox.net/web-development/unexpected-ddos-blocking-china-with-ipset-and-iptables/我一直在尝试使用 IPTables 来阻止来自中国防火墙的重定向 DDoS 流量，方法是阻止带有“Bittorrent”字符串的请求，并使用最新的 IP 列表简单地阻止来自中国的所有 IPhttp://www.ipdeny.com/ipblocks/data/countries/cn.zone。
我的防火墙看起来像这样。
*filter
# Allow all loopback (lo0) traffic and drop all traffic to 127/8 that doesn't use lo0
-A INPUT -i lo -j ACCEPT
-A INPUT -d 127.0.0.0/8 -j REJECT
# Accept all established inbound connections
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
# Block anything from China
# These rules are pulled from ipset's china list
# The source file is at /etc/cn.zone (which in turn is generated by a shell script at /etc/block-china.sh )
-A INPUT -p tcp -m set --match-set china src -j DROP
# Block bittorent
-A INPUT -p tcp --dport 80 -m string --algo bm --string "Bittorrent" --to 1000 -j DROP
-A INPUT -p tcp --dport 80 -m string --algo bm --string "GET /announce" --to 1000 -j DROP
# Limit connection speed to avoid DDOS
-A INPUT -p tcp --dport 80 -m state --state NEW -m limit --limit 50/minute --limit-burst 200 -j ACCEPT
# Allow all outbound traffic - you can modify this to only allow certain traffic
-A OUTPUT -j ACCEPT
# Allow HTTP and HTTPS connections from anywhere (the normal ports for websites and SSL).
-A INPUT -p tcp --dport 80 -j ACCEPT
-A INPUT -p tcp --dport 443 -j ACCEPT
# Allow SSH connections
#
# The -dport number should be the same port number you set in sshd_config
#
-A INPUT -p tcp -m state --state NEW --dport 2222 -j ACCEPT
# Allow ping
-A INPUT -p icmp -j ACCEPT
# Log iptables denied calls
-A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7
# Drop all other inbound - default deny unless explicitly allowed policy
-A INPUT -j DROP
-A FORWARD -j DROP
COMMIT
但是，防火墙似乎根本不起作用。中国 IP 仍然充斥在 Apache 日志中，并且“Bittorrent”字符串仍然出现在 Apache 日志中。我似乎被不在禁止列表中的 IP 淹没了（ipdeny 的列表有多准确？），并且 IPtables 字符串正则表达式似乎根本不起作用，因为仍然会出现类似以下的日志。
110.255.172.42 - - [26/Apr/2015:18:05:41 +1200] "GET /announce.php?info_hash=M%3A%89%E1%86%9D%60%A7I%23%D6%99r%04%D7t%06%5F%A6%CC&peer_id=%2DSD0100%2D%E9%B1%EF%11A%CC%FB%94%EDl%23%8A&ip=101.28.113.60&port=8644&uploaded=1503508047&downloaded=1503508047&left=0&numwant=200&key=9253&compact=1 HTTP/1.0" 410 225 "-" "Bittorrent"
还，http://www.blockedinchina.net/仍然显示我的网站在中国境内可以访问。
运行 sudo iptables -L 得到以下结果：
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- anywhere anywhere
REJECT all -- anywhere 127.0.0.0/8 reject-with icmp-port-unreachable
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
DROP tcp -- anywhere anywhere match-set china src
DROP tcp -- anywhere anywhere tcp dpt:http STRING match "Bittorrent" ALGO name bm TO 1000
DROP tcp -- anywhere anywhere tcp dpt:http STRING match "GET /announce" ALGO name bm TO 1000
ACCEPT tcp -- anywhere anywhere tcp dpt:http state NEW limit: avg 50/min burst 200
ACCEPT tcp -- anywhere anywhere tcp dpt:http
ACCEPT tcp -- anywhere anywhere tcp dpt:https
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:2222
ACCEPT icmp -- anywhere anywhere
LOG all -- anywhere anywhere limit: avg 5/min burst 5 LOG level debug prefix "iptables denied: "
DROP all -- anywhere anywhere
Chain FORWARD (policy ACCEPT)
target prot opt source destination
DROP all -- anywhere anywhere
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- anywhere anywhere
有人知道为什么我的防火墙可能无法工作吗？
答案1
我遇到了同样的问题，因此这在我的网络服务器上有效：
iptables -I INPUT -m string --string "announce.php" --algo kmp --to 65535 -j TARPIT
我在顶部添加了这条规则。你这个猫用的是 DROP 而不是 TARPIT（是的，我是个坏人，被迫受苦的中国人 :-D）。