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Drop access to unused ports

This commit is contained in:
Bob Mottram 2014-02-24 22:05:33 +00:00
parent 41d9636d16
commit b86389bd99
1 changed files with 46 additions and 5 deletions
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51
beaglebone.txt
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@ -447,7 +447,7 @@ apt-get install fail2ban
-- NBC News article: /War on Anonymous: British Spies Attacked Hackers, Snowden Docs Show/
#+END_VERSE
A basic firewall limits the maximum rate at which connections can be made, and this helps to defend against various kinds of DDOS attack.
A basic firewall limits the maximum rate at which connections can be made and closes any unused ports, and this helps to defend against various kinds of DDOS attack.
#+BEGIN_SRC: bash
apt-get install portsentry
@ -483,10 +483,10 @@ Enter the following:
#+BEGIN_SRC: bash
#!/bin/bash
# enable syn cookies
# Enable syn cookies
echo 1 > /proc/sys/net/ipv4/tcp_syncookies
# other settings
# Other settings
echo 1 > /proc/sys/net/ipv4/tcp_keepalive_probes
echo 2 > /proc/sys/net/ipv4/tcp_synack_retries
echo 1 > /proc/sys/net/ipv4/tcp_syn_retries
@ -497,6 +497,44 @@ iptables -P INPUT ACCEPT
iptables -F
iptables -X
# Drop access to unused ports
iptables -A INPUT -p tcp --destination-port 1 -j DROP
iptables -A INPUT -p tcp --destination-port 7 -j DROP
iptables -A INPUT -p tcp --destination-port 109:111 -j DROP
iptables -A INPUT -p tcp --destination-port 995 -j DROP
iptables -A INPUT -p tcp --destination-port 139 -j DROP
iptables -A INPUT -p tcp --destination-port 6000:6001 -j DROP
iptables -A INPUT -p tcp --destination-port 9 -j DROP
iptables -A INPUT -p tcp --destination-port 79 -j DROP
iptables -A INPUT -p tcp --destination-port 515 -j DROP
iptables -A INPUT -p tcp --destination-port 4001 -j DROP
iptables -A INPUT -p tcp --destination-port 1524 -j DROP
iptables -A INPUT -p tcp --destination-port 1080 -j DROP
iptables -A INPUT -p tcp --destination-port 512:514 -j DROP
iptables -A INPUT -p tcp --destination-port 31337 -j DROP
iptables -A INPUT -p tcp --destination-port 2000:2001 -j DROP
iptables -A INPUT -p tcp --destination-port 12345 -j DROP
iptables -A INPUT -p tcp --destination-port 32771:32774 -j DROP
iptables -A INPUT -p tcp --destination-port 4000 -j DROP
iptables -A INPUT -p udp --destination-port 1 -j DROP
iptables -A INPUT -p udp --destination-port 7 -j DROP
iptables -A INPUT -p udp --destination-port 109:111 -j DROP
iptables -A INPUT -p udp --destination-port 995 -j DROP
iptables -A INPUT -p udp --destination-port 139 -j DROP
iptables -A INPUT -p udp --destination-port 6000:6001 -j DROP
iptables -A INPUT -p udp --destination-port 9 -j DROP
iptables -A INPUT -p udp --destination-port 79 -j DROP
iptables -A INPUT -p udp --destination-port 515 -j DROP
iptables -A INPUT -p udp --destination-port 4001 -j DROP
iptables -A INPUT -p udp --destination-port 1524 -j DROP
iptables -A INPUT -p udp --destination-port 1080 -j DROP
iptables -A INPUT -p udp --destination-port 512:514 -j DROP
iptables -A INPUT -p udp --destination-port 31337 -j DROP
iptables -A INPUT -p udp --destination-port 2000:2001 -j DROP
iptables -A INPUT -p udp --destination-port 12345 -j DROP
iptables -A INPUT -p udp --destination-port 32771:32774 -j DROP
iptables -A INPUT -p udp --destination-port 4000 -j DROP
# Make sure NEW incoming tcp connections are SYN packets
iptables -A INPUT -p tcp ! --syn -m state --state NEW -j DROP
@ -511,11 +549,11 @@ iptables -A INPUT -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j DROP
# Incoming malformed NULL packets:
iptables -A INPUT -p tcp --tcp-flags ALL NONE -j DROP
# drop UDP to used ports
# Drop UDP to used ports
iptables -A INPUT -p udp --match multiport --dports 70,80,443,143,6670,993,5060,5061,25 -j DROP
iptables -A INPUT -p udp --match multiport --dports 465,22,5222,5223,5269,5280,5281,8444 -j DROP
# limit ssh logins
# Limit ssh logins
iptables -A INPUT -p tcp --dport 22 -m limit --limit 3/minute --limit-burst 1 -j ACCEPT
# Limit web connections
@ -525,6 +563,9 @@ iptables -A INPUT -p tcp --dport 443 -m limit --limit 10/minute --limit-burst 1
# Limit number of XMPP connections
iptables -A INPUT -p tcp --match multiport --dports 5222:5223,5269,5280:5281 -m limit --limit 10/minute --limit-burst 1 -j ACCEPT
# Limit NNTP connections
iptables -A INPUT -p tcp --dport 119 -m limit --limit 5/minute --limit-burst 1 -j ACCEPT
# Limit IRC connections
iptables -A INPUT -p tcp --dport 6666:6670 -m limit --limit 10/minute --limit-burst 1 -j ACCEPT