What happens when I change iptables default policy to drop?
After changing the INPUT, FORWARD, OUTPUT policies to DROP, All the incomming/outgoing/forwarding connections are dropped (Denied) by firewall. So you need to open every INPUT, FORWARD, OUTPUT connections in firewall/iptables with rules. If you change the default OUTPUT policy to DROP you cannot communicate with other systems/networks .
How to allow outgoing traffic in iptables command?
You may want to allow outgoing traffic of all established connections, which are typically the response to legitimate incoming connections. This command will allow that: sudo iptables -A OUTPUT -m conntrack –ctstate ESTABLISHED -j ACCEPT
Is the iptables firewall included in Linux distributions?
Iptables is the software firewall that is included with most Linux distributions by default. This cheat sheet-style guide provides a quick reference to iptables commands that will create firewall rules are useful in common, everyday scenarios.
How to make an iptables allow both HTTP and HTTPS?
If you want to allow both HTTP and HTTPS traffic, you can use the multiport module to create a rule that allows both ports. To allow all incoming HTTP and HTTPS (port 443) connections run these commands: sudo iptables -A INPUT -p tcp -m multiport –dports 80,443 -m conntrack –ctstate NEW,ESTABLISHED -j ACCEPT
What are the ports in Debian-iptables policy input drop?
PORT STATE SERVICE 22 / tcp open ssh 53 / tcp open domain 80 / tcp open http 111 / tcp open rpcbind 139 / tcp open netbios-ssn 445 / tcp open microsoft-ds What might be going on? I believe these ports 111 139 445 were not to appear
What do input and output need in http-iptables?
INPUT needs a source ip and destination port and OUTPUT needs a destination ip and source port. Traffic coming in will be NEW or ESTABLISHED and traffic going out from server services (in a client/server design) will be ESTABLISHED.