Suggest an editImprove this articleRefine the answer for “What types of firewall are there?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)There are several types of firewall: **packet filtering, stateful, application, WAF, proxy, and Next-Generation Firewall (NGFW)**, each operating at its own layer and with a different depth of traffic analysis. **Key point:** an NGFW effectively combines several security tools into one device.Shown above the full answer for quick recall.Answer (EN)Image## Main types of firewall ### 1. Packet Filtering Firewall **The simplest type of firewall.** **How it works:** - checks each packet individually; - looks at IP addresses, protocols and ports; - does not "remember" previous packets. **Pros:** - fast; - simple to implement. **Cons:** - does not understand the connection's context; - weak protection. Works mostly at the **network layer (L3)**. --- ### 2. Stateful Firewall **The most common type of firewall.** **How it works:** - tracks connection state; - understands which packet is a request and which is a reply; - passes only legitimate traffic. **Pros:** - much safer than packet filtering; - protects well against many attacks. **Cons:** - requires more resources. Works at the **network and transport layers (L3-L4)**. --- ### 3. Application Firewall (Application Layer Firewall) **A firewall at the application layer.** **How it works:** - analyzes traffic content; - understands application protocols (HTTP, FTP, SMTP); - can block attacks at the application layer. **Pros:** - high accuracy; - protection against attacks on applications. **Cons:** - slower; - harder to configure. Works at the **application layer (L7)**. --- ### 4. Web Application Firewall (WAF) **A specialized firewall for web applications.** **How it works:** - protects HTTP/HTTPS; - blocks SQL injection, XSS and other web attacks. **Pros:** - excellent protection for websites; - filters web traffic specifically. **Cons:** - protects only web applications. Often used together with a regular firewall. --- ### 5. Proxy Firewall **Works as an intermediary between client and server.** **How it works:** - the client connects to the proxy; - the proxy connects to the server itself; - there is no direct connection. **Pros:** - hides the internal network; - can filter content. **Cons:** - latency; - harder to administer. --- ### 6. Next-Generation Firewall (NGFW) **A modern, "smart" firewall.** **What it can do:** - stateful filtering; - application analysis; - IDS/IPS; - user control; - SSL inspection. It effectively combines **several security tools in one**. --- ## Brief comparison | Firewall type | Layer | Characteristic | |---|---|---| | Packet filtering | L3 | Simple filtering | | Stateful | L3-L4 | Understands connections | | Application | L7 | Analyzes content | | WAF | L7 | Protects web applications | | Proxy | L7 | Works as an intermediary | | NGFW | L3-L7 | Maximum protection |For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.