See the following configuratonįirst load the following module to make sure passive ftp connections are not rejected modprobe ip_conntrack_ftpĪllow FTP connections on port 21 incoming and outgoing iptables -A INPUT -p tcp -m tcp -dport 21 -m conntrack -ctstate ESTABLISHED,NEW -j ACCEPT -m comment -comment 'Allow ftp connections on port 21'

So to make data transfer possible you'd need to enable port 20 as well. Port 21 is used to establish the connection. Your ftp server needs a channel to transfer data.

If iptables is enforcing, then transfer failed. If I disable iptables, I am able to transfer my backup from another machine to FTP. Loading additional iptables modules: ip_conntrack_netbios_nīut the problem is not with that module, as I tried unloading it and still no luck. A OUTPUT -p tcp -m tcp -sport 20 -j ACCEPTĪlso, by default, ip_conntrack_netbios_n module is getting loaded. A INPUT -j REJECT -reject-with icmp-port-unreachable A INPUT -p tcp -m state -state ESTABLISHED -j ACCEPT A INPUT -p tcp -m tcp -dport 21 -j ACCEPT To list iptables rules use the following command.This is my /etc/sysconfig/iptables file. Now check the iptables service status using below command.

sudo yum install iptables-servicesĪfter installing enable iptables service and start using below commands. Now install iptables service using yum package manager using the following command. Main PID: 7411 (code=exited, status=0/SUCCESS)įeb 27 11:02:18 svr10 systemd: Started firewalld - dynamic firewall daemon.įeb 27 11:09:36 svr10 systemd: Stopping firewalld - dynamic firewall daemon.įeb 27 11:09:37 svr10 systemd: Stopped firewalld - dynamic firewall daemon. Now check firewalld status sudo systemctl status firewalldĪctive: inactive (dead) since Fri 11:09:37 EST 56s ago To completely disable firewalld service use following commands.

Before installing and using iptables services on CentOS and Red Hat 7 systems, we need to disable firewalld service.

Centos iptables