# Firewall symbol

Canonical URL: https://eloragrid.ai/symbols/iec-firewall-symbol
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: FW
Drawing use: Schematic
Reference families: IEC

Network symbol for a firewall, drawn as a brick wall, separating network zones on communication drawings.

## In plain English

### What does Firewall mean?

A firewall controls traffic between network zones according to rules, and is drawn on network diagrams as a brick wall block. Industrial drawings place it between the corporate network and control networks or between a remote access link and the plant.

### A simple example

Many industrial routers include firewall functions, so the drawing may show the firewall as a logical function inside a router. Where a separate appliance is used, its power and rack position appear on the electrical drawing. The symbol does not show the rule set or zones. Those belong in the cyber security documentation.

### What the drawings help you do

Identify the zones on each side. Check whether it is a separate device or a router function. A router connects networks; a firewall filters traffic by policy, even when both are in one device.

### This particular reference

Network symbol for a firewall, drawn as a brick wall, separating network zones on communication drawings. A router connects networks; a firewall filters traffic by policy, even when both are in one device.

### Terms

- Signal: Electrical information passed between devices, rather than necessarily the main power supply.
- Schematic: A drawing showing function and connections rather than physical appearance.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [Industrial cellular routers and gateways](https://www.westermo.com/products/routers-and-gateways/cellular-routers-and-gateways)


## What it represents

A firewall controls traffic between network zones according to rules, and is drawn on network diagrams as a brick wall block. Industrial drawings place it between the corporate network and control networks or between a remote access link and the plant.
Many industrial routers include firewall functions, so the drawing may show the firewall as a logical function inside a router. Where a separate appliance is used, its power and rack position appear on the electrical drawing. The symbol does not show the rule set or zones. Those belong in the cyber security documentation.

## How to read it

- Identify the zones on each side.
- Check whether it is a separate device or a router function.

## Information to show or reference

- Label zones.
- State device or function.
- Show power if a separate appliance.

## Important distinction

A router connects networks; a firewall filters traffic by policy, even when both are in one device.

## Facts

- Function: Traffic filtering between zones
- Graphic form: Brick wall block
- Preview: Independent educational concept; plan symbols for this device vary between legends, so read the project key

## Public references

- [Industrial cellular routers and gateways](https://www.westermo.com/products/routers-and-gateways/cellular-routers-and-gateways) — Westermo. Public product family page describing routers and gateways, including stateful firewall functions.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.