---
title: "OPNsense - Maintenance time estimate"
author: Petar Cubela
date: July 03, 2024
geometry: margin=1.5cm
output: pdf_document
---

## Intro

Let us roughly calculate the time needed to maintain a OPNsesne firewall.
Here we assumer that the firewall is already configured. Thus we are looking at standard maintenance of the device.

## OPNcentral

We are using OPNcentral which is able to monitor arbitrary numbers of OPNsense firewalls: 

- it manually/automatically creates backups of all integrated firewalls 
- backups can be read and compared for any firewall integrated in OPNcentral
- firmware, services and resources status of each OPNsense firewall can be managed via OPNcentral
- plugin configuration can be managed and send to each firewall via OPNcentral 

## Time Consumption

- updates have to been done regularly which can be checked and updated for all firewalls simultaneously via OPNcentral (~ 1h per month for all firewalls!)
- in general the firewall will run flawlessly once setup without much interaction as long as nothing complicated has to be changed. 
- changes in the configuration for known features should be in general simple (~1h per month for all firewalls!)
- changes for new plugins should take longer depending on the plugin but happens seldom (few/many days depending on plugin once each half year)
- OpenVPN integration is better integrated in Sophos. We will probably need to export the client configuration for each user (~ 1h per week for each firewall, depending on the number of users requiring vpn)

- there can be unexpected problems with the firewall in production use which we have to test and can not assess pre-usage (~ 1h per month a firewall)

### Estimation

- ~ 1h/month for updates
- ~ 1h/month for small config changes
- ~ up to days for configuring new desired plugins. happens once per year/half year?
- ~ 1h/month for vpn client export
- ~ 1h/month for unexpected issues/tickets 

Which summarizes to **~ 4 hours per month** and more when new not-so-known plugins have to be configured.