Smoothwall Express 3.1 was released in 2014. That is 12 years without a major release for a Linux-based security appliance. Let's look at what that means technically.
What "no major release" means for a security appliance
A Linux-based firewall distribution depends on several upstream components that evolve continuously:
- Linux kernel: LTS kernels have 6-year support cycles. The kernel shipped with Smoothwall Express 3.1 (based on CentOS 6 era) is several major versions behind current LTS (6.x).
- iptables / nftables: iptables has been superseded by nftables in modern distributions. Smoothwall Express uses iptables.
- OpenSSL: Multiple major versions have been released since 2014, including TLS 1.3 support (OpenSSL 1.1.1+). Older OpenSSL versions cannot negotiate TLS 1.3 connections.
- Squid: Squid 6.x shipped in 2023 with significant security improvements. Smoothwall Express ships an older Squid branch.
The OpenSSL / TLS 1.3 problem in particular
Many modern servers prefer or require TLS 1.3. A proxy running an OpenSSL version that predates TLS 1.3 support will negotiate TLS 1.2 at best — or fail to connect entirely if the upstream server enforces TLS 1.3 minimum.
For a security gateway that is supposed to inspect web traffic, this is a meaningful capability gap: you cannot inspect TLS 1.3 traffic you cannot terminate.
Feature gaps compared to a modern UTM
Smoothwall Express was designed as a simple firewall and proxy. Features that exist in current UTMs but not in Smoothwall Express:
✅ Stateful firewall
✅ Basic web proxy (Squid)
✅ Basic URL filtering
⚠️ Web antivirus (ClamAV, but outdated)
❌ SSL inspection / TLS MITM
❌ Web Application Firewall
❌ Reverse proxy
❌ Load balancer
❌ Multi-WAN with failover
❌ QoS / traffic shaping beyond basics
❌ LDAP/AD integration for per-user filtering
❌ Centralised multi-site management
Smoothwall UTM: the commercial version
Smoothwall Ltd. (now owned by Family Zone Cyber Safety) maintains a separate commercial product — Smoothwall UTM — that has received active development. It includes SSL inspection, AD integration, and modern content filtering. It is priced for the education market and has E-Rate eligibility in the US.
If you need Smoothwall specifically for education-sector compliance (E-Rate, safeguarding requirements), Smoothwall UTM remains relevant. For general SMB use, you are paying education-market pricing for a product optimised for a different use case.
Migration path technical considerations
Moving from Smoothwall Express to a modern UTM:
1. Firewall rule export: Smoothwall rules are stored in flat files, not an exportable standard format. Rules must be manually translated to the target platform's syntax.
2. URL filtering: Smoothwall uses SquidGuard with MESD blocklists. Modern replacements use updated category databases — mapping between category taxonomies requires review.
3. Network topology: Smoothwall uses a red/green/orange/blue zone model. Map these to the equivalent interface/zone model on the target platform before migration.
4. Parallel operation: Run the new appliance in parallel on a test segment for at least a week before cutover. Smoothwall's configuration edge cases may not be immediately apparent.
CacheGuard as a migration target provides LDAP/AD integration for per-user URL filtering, SSL inspection, WAF, and a fully active development cycle — with a kernel and OpenSSL version current as of 2026.
→ https://www.cacheguard.com/smoothwall-alternative/
Originally published on the CacheGuard Blog. CacheGuard is free and open source — GitHub.
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