> ```
>
> Please make sure this step is carried out, without this step PostgreSQL notification targets will not work,
> an error message will be shown on the console upon server upgrade/restart, make sure to follow the above
> instructions appropriately. For further questions please join our <https://slack.min.io>

```sh
firewall-cmd --zone=public --add-port=9000/tcp --permanent
```

Note that `permanent` makes sure the rules are persistent across firewall start, restart or reload. Finally reload the firewall for changes to take effect.

```sh
firewall-cmd --reload
```

### iptables

- **MinIO chooses the largest EC set size which divides into the total number of drives or total number of nodes given - making sure to keep the uniform distribution i.e each node participates equal number of drives per set**.
- **Each object is written to a single EC set, and therefore is spread over no more than 16 drives.**