Fun lesson from today: don’t blindly clear\/flush your iptables.<\/p>\n
If you are remotely managing a system, then make sure you run this: before you run this: It turns out there are people who will write default block (“policy DROP”) style rules (instead of the using a default “policy ACCEPT” and ending with REJECTs\/DROPs at the end that match everything). If the default policy is not ACCEPT, then clearing the rules will immediately remove your ssh access to the machine. <\/p>\n The lack of a default “policy REJECT” is one reason you will see more “policy ACCEPT” – because then, at the end, you can choose between REJECT or DROP. If you write your rules “in the other direction”, you loose the flexibility to choose – you must DROP. There are numerous posts on why DROP is not necessarily better than REJECT. (“Attackers don’t really feel any pain with DROP, but your legitimate users sure do”.)<\/p>\n","protected":false},"excerpt":{"rendered":" Fun lesson from today: don’t blindly clear\/flush your iptables. If you are remotely managing a system, then make sure you run this: sudo iptables -P INPUT ACCEPT sudo iptables -P FORWARD ACCEPT sudo iptables -P OUTPUT ACCEPT before you run … Continue reading
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\n sudo iptables -P INPUT ACCEPT
\n sudo iptables -P FORWARD ACCEPT
\n sudo iptables -P OUTPUT ACCEPT
\n<\/code><\/p>\n
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\n sudo iptables -F
\n<\/code><\/p>\n