How to configure firewall rules using iptables on RancherOS
- A RancherOS v1.5.x host
The runcmd option in cloud-config can be used to run commands, such as iptables rules, to set firewall rules on a RancherOS host. For example the following can be used to disable SSH access on port 22.
#cloud-config runcmd: - "iptables -A INPUT -p tcp --destination-port 22 -j DROP"
The above snipet can be placed in /var/lib/rancher/conf/cloud-config.d/xxx.yaml, or added to the initial config while installing RancherOS. It will be executed every time RancherOS is booted.
You can use the following iptables command to view the status of the rules:
$ iptables -t filter -nv -L INPUT Chain INPUT (policy ACCEPT 321 packets, 41200 bytes) pkts bytes target prot opt in out source destination 9 523 DROP tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:22
More information on running command on boot can be found here.