nftables runs as the active kernel backend on roughly 70–75% of Linux server installations in 2026. The shift happened quietly — most administrators still type iptables or ufw commands while nftables processes the rules underneath. This article covers verified adoption data, distribution defaults, cloud deployment rates, and security metrics for the three primary Linux firewall tools: iptables, nftables, and UFW.
Linux Firewall Statistics (2026)
- nftables is the default kernel backend on every major Linux distribution released after 2019.
- firewalld covers an estimated 45–50% of Linux server installations, driven by RHEL’s 43.1% enterprise market share.
- UFW runs on 34–40% of deployments, with Ubuntu holding over 60% of public cloud Linux instances.
- Kubernetes production deployment reached 82% in 2025; Linux powers 78% of those clusters globally.
- As of October 2025, iptables carried multiple active CVEs requiring patches — nftables had no major CVE on record.
Linux Firewall Backend Defaults by Distribution
The firewall tool an administrator interacts with depends almost entirely on which Linux distribution they run. The actual packet filtering happens at the kernel level — and that backend has moved to nftables across all actively maintained distributions.
| Distribution | Default Frontend | Default Backend | nftables Default Since |
|---|---|---|---|
| RHEL 8+ | firewalld | nftables | 2019 |
| RHEL 7 (legacy) | firewalld | iptables | N/A |
| Ubuntu 20.10+ | UFW | nftables | 2020 |
| Ubuntu 18.04 LTS (legacy) | UFW | iptables | N/A |
| Debian 10+ | nftables (direct) | nftables | 2019 |
| Fedora 32+ | firewalld | nftables | 2020 |
| AlmaLinux 8+ | firewalld | nftables | 2021 |
| Rocky Linux 8+ | firewalld | nftables | 2021 |
| CentOS 7 (legacy) | firewalld | iptables | N/A |
Source: Netfilter Project; Red Hat Documentation; Debian Wiki; Ubuntu Security Documentation
On Ubuntu 22.04 and later, running an iptables command routes automatically through the nftables backend via the iptables-nft compatibility layer. The Netfilter Project has placed iptables in legacy maintenance mode and directs all new deployments to nftables.
iptables vs nftables vs UFW: Market Share in 2026
No single survey tracks the iptables-versus-nftables split across all Linux servers globally. Combining distribution market share data with each distribution’s default backend produces the following working estimate.
| Firewall Layer | Estimated Share | Basis |
|---|---|---|
| nftables (active kernel backend) | ~70–75% | Default on all post-2019 distributions |
| iptables (native, no shim) | ~25–30% | Legacy systems: RHEL 7, CentOS 7, Ubuntu 18.04 |
| UFW (frontend) | ~34–40% | Default on all Debian/Ubuntu family systems |
| firewalld (frontend) | ~45–50% | Default on RHEL, Fedora, AlmaLinux, Rocky Linux |
| Direct nftables/iptables (no frontend) | ~10–15% | Arch, Gentoo, Slackware, custom enterprise setups |
Source: Command Linux — Linux Distribution Market Share Statistics 2025; SQ Magazine — Linux Statistics 2025; Canonical
Most administrators on Red Hat systems type firewall-cmd commands and never touch nft syntax. Most Ubuntu administrators run ufw allow 22 without knowing nftables is processing the rule. Direct nftables usage stays concentrated among Debian administrators and those running Arch or Gentoo.
nftables Adoption in Cloud and Kubernetes Environments
Cloud-native infrastructure has pushed nftables adoption faster than traditional server deployments. Linux’s dominance in container orchestration means nftables now handles firewall rules across a large share of global production workloads.
| Metric | Value | Period |
|---|---|---|
| Kubernetes production deployment rate | 82% | 2025 |
| Linux-powered Kubernetes clusters | 78% | 2024 |
| Cloud workloads running on Linux | 49.2% | Q2 2025 |
| Organizations adopting cloud-native techniques | 98% | 2025 |
| Docker container market size | $6.12 billion | 2025 |
Source: CNCF Annual Cloud Native Survey 2025; Command Linux; Statista; Market Growth Reports
Kubernetes production deployment reached 82% in 2025, up from 80% in 2024 and 66% in 2023. By 2025, both Docker and Kubernetes tooling had updated their Netfilter integration to handle nftables backends cleanly, resolving the compatibility conflicts that affected Fedora 32 deployments when firewalld first switched backends.
Linux Firewall Security: nftables vs iptables CVE Comparison
Security posture is a measurable factor in the migration from iptables to nftables. The architectural differences between the two produce directly different vulnerability profiles.
| Security Metric | iptables | nftables |
|---|---|---|
| Major CVEs (as of October 2025) | Multiple active CVEs requiring patches | No major CVE recorded |
| Protocol handling | Separate binaries for IPv4, IPv6, ARP, bridging | Single unified virtual machine |
| Code duplication risk | High — duplicated across four separate tools | Low — consolidated codebase |
| Atomic rule updates | No — requires full rule-set refresh | Yes — no traffic interruption |
| Rule processing | Sequential top-to-bottom | Compiled bytecode in kernel VM |
Source: SafeIT Experts Firewall Effectiveness Comparison, October 2025; Netfilter Project; Hoplon InfoSec
iptables splits protocol-specific code across iptables, ip6tables, arptables, and ebtables. nftables consolidates all of this into one subsystem, reducing the attack surface from code duplication. SafeIT Experts’ October 2025 analysis found no major CVE against nftables at the time of review, while other firewall solutions carried active CVEs requiring urgent patching.
Enterprise Linux Firewall Deployment in 2026
Enterprise Linux server infrastructure tracks closely with OS market share. RHEL’s 43.1% enterprise share makes firewalld-over-nftables the single most common enterprise firewall configuration in 2026.
| Enterprise Metric | Value |
|---|---|
| Linux server OS market share (2024) | 44.8% |
| RHEL enterprise Linux market share (2025) | 43.1% |
| Ubuntu general deployment share (2025) | 33.9% |
| Ubuntu public cloud Linux instances | 60%+ |
| Linux-powered web-facing servers (2025) | 78.3% |
| Fortune 500 running mission-critical Linux workloads | 72.6% |
| Global Linux OS market valuation (2024) | $21.97 billion |
Source: SQ Magazine — Linux Statistics 2025; Canonical; Fortune Business Insights
Ubuntu’s 33.9% deployment share plus its dominance in public cloud — over 60% of public cloud Linux instances per Canonical — makes UFW-over-nftables the second most common setup. Together, these two frontend-backend combinations cover roughly 77% of the enterprise Linux server market.
Remaining iptables Deployments
Systems running RHEL 7 or CentOS 7 are the largest source of active iptables deployments in production. CentOS 7 reached end of life in June 2024. RHEL 7 entered Extended Life Phase. These installations are shrinking but persist in environments with slow upgrade cycles.
Why iptables Persists on Production Linux Servers
Long-running servers carry firewall configurations written as iptables scripts. These stay in place even after an OS upgrade, particularly when administrators use the iptables-nft compatibility layer, which accepts iptables syntax while routing rules to the nftables engine.
The iptables-translate tool converts iptables rules to nftables syntax and cuts migration friction. Despite that, industry commentary from TuxCare, Zenarmor, and linuxmind.dev consistently finds iptables prevalent in legacy infrastructure where firewall rules are treated as set-and-forget configuration.
Automation tooling built around iptables — Ansible playbooks, shell scripts, CI/CD pipelines — also slows the transition. The kernel-level shift to nftables happens automatically on modern distributions, while the management layer stays on iptables syntax for years.
FAQ
What is the most widely used Linux firewall tool in 2026?
firewalld is the most common frontend, covering an estimated 45–50% of Linux server deployments. It runs on top of nftables as the kernel backend on all modern Red Hat-family distributions including RHEL 8+, AlmaLinux, and Rocky Linux.
Is iptables still actively used in 2026?
Yes. An estimated 25–30% of Linux servers still run native iptables, mainly on legacy systems such as RHEL 7 and CentOS 7. On modern distributions, iptables commands route through nftables automatically via a compatibility shim.
When did major distributions switch from iptables to nftables?
The shift began in 2019 with RHEL 8 and Debian 10. Ubuntu followed with version 20.10 in late 2020. Every major distribution released after 2019 ships nftables as its default kernel backend.
Is nftables more secure than iptables?
SafeIT Experts’ October 2025 analysis found no major CVE against nftables, while iptables carried multiple active CVEs. nftables consolidates protocol handling into a single codebase, reducing the attack surface compared to iptables’ four separate binaries.
What percentage of Kubernetes clusters run on Linux?
Linux powers 78% of Kubernetes clusters globally as of 2024. Kubernetes itself reached an 82% production deployment rate in 2025, making nftables the dominant firewall backend across container environments by default.
Netfilter Project — nftables architecture and iptables legacy status
CNCF Annual Cloud Native Survey 2025 — Kubernetes production and cloud-native adoption rates
Red Hat Documentation — RHEL firewall backend defaults and nftables migration
Ubuntu Security Documentation — UFW and nftables compatibility layer
