This is a sample iptables statement marking packets coming in on eth0: iptables -t mangle -A PREROUTING -i eth0 -j MARK --set-mark 6 SEE ALSO tc(8), iptables(8), iptables-extensions(8) iproute2 21 Oct 2015 Firewall mark classifier in tc(8)

iptables -A INPUT -i eth0 -p tcp --dport 22 -j ACCEPT. You can verify modified set of rules by seeing /etc/sysconfig/iptables file (as shown in Figure 10). Figure 6: Stopping and starting iptables Figure 7: /etc/sysconfig/iptables Figure 8: Restarting iptables Figure 9: Appending a rule Figure 10: /etc/sysconfig/iptables after adding a rule sudo iptables -t nat -A POSTROUTING --out-interface eth1 -j MASQUERADE sudo iptables -A FORWARD --in-interface eth0 -j ACCEPT All of the forwarded traffic will traverse the FORWARD chain. To filter packets you'll now have to create rules on that chain specifying which interface is incoming/outgoing instead of using the INPUT/OUTPUT chains. Allow MySQL connections to eth0 network interface Here’s the syntax for iptables and nftables: [email protected] :~$ iptables-translate -A INPUT -i eth0 -p tcp --dport 3306 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT nft add rule ip filter INPUT iifname eth0 tcp dport 3306 ct state new,established counter accept iptables -A FORWARD -i eth0 -p tcp --dport 80 -d 172.31.0.23 -j ACCEPT This rule allows forwarding of incoming HTTP requests from the firewall to its intended destination of the Apache HTTP Server server behind the firewall. iptables -A INPUT -s 11.22.33.44 -i eth0 -j DROP Or an specific port. iptables -A INPUT -s 11.22.33.44 -p tcp -dport 22 -j DROP Using a Network and not only one IP. iptables -A INPUT -s 11.22.33.0/24 -j DROP Block traffic from a specific MAC address. Suppose you want to bloc traffic some a MAC address instead of an IP address.

Apr 11, 2020 · auto eth0 iface eth0 inet dhcp pre-up iptables-restore < /etc/iptables.rules post-down iptables-restore < /etc/iptables.downrules You may also want to keep information from byte and packet counters. sudo sh -c "iptables-save -c > /etc/iptables.rules" Then you'll need to configure iptables to forward the packets from your internal network, on /dev/eth1, to your external network on /dev/eth0. You do this will the following commands: # /sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE # /sbin/iptables -A FORWARD -i eth0 -o eth1 -m state --state RELATED,ESTABLISHED -j ACCEPT # /sbin/iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT

Sep 26, 2018 · Block Connections to a Network Interface iptables -A INPUT -i eth0 -s 192.168.252.10 -j DROP; Block Connections to a Network Interface iptables -A INPUT -i eth0 -s 192.168.252.10 -j DROP; Allow All Incoming SSH iptables -A INPUT -p tcp –dport 22 -m conntrack –ctstate NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -p tcp –sport 22 -m

Dec 19, 2011 · The problem with that setup is that iptables does not seem to accept a virtual designation for a NIC in its statements. eth0 is acceptable but eth0:1 is not. Therefore I had no choice but to install another NIC on the WAN side and designate it eth2. Sep 26, 2018 · Block Connections to a Network Interface iptables -A INPUT -i eth0 -s 192.168.252.10 -j DROP; Block Connections to a Network Interface iptables -A INPUT -i eth0 -s 192.168.252.10 -j DROP; Allow All Incoming SSH iptables -A INPUT -p tcp –dport 22 -m conntrack –ctstate NEW,ESTABLISHED -j ACCEPT iptables -A OUTPUT -p tcp –sport 22 -m iptables -A INPUT -m statistic --mode random --probability 0.01 -j DROP Above will drop an incoming packet with a 1% probability. Be careful, anything above about 0.14 and most of you tcp connections will most likely stall completely. Take a look at man iptables and search for "statistic" for more information. $> iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT $> iptables -A INPUT -m state --state NEW -i ! eth0 -j ACCEPT $> iptables -P INPUT DROP #only if the first two are succesful $> iptables -A FORWARD -i eth0 -o eth0 -j REJECT