One box between your office and the internet — firewall, web filtering, VPN and reports in a single rack of apps. Here is the honest setup order: installer, wizard, interfaces, mode, first apps, update and backup.
Arista NG Firewall — sold today as Arista Edge Threat Management NG Firewall — is the software that used to be called Untangle NG Firewall. It turns a spare PC or a virtual machine into your network's gateway: every device in the office reaches the internet through it, and it filters, logs and guards that traffic with a rack of switch-on apps. This guide follows the same order as the video: get the installer the official way, prepare hardware with two network cards, run the wizard without guessing, choose the working mode, light up the free core apps, then update and back up before calling it done.
NG Firewall is the gateway software sold today as Arista Edge Threat Management (ETM) NG Firewall. Arista Networks bought Untangle in 2022 and renamed the product, so older guides, forum posts and even the box itself may still say Untangle — it is the same product line, now on the 17.x version series. It installs on your own hardware or as a virtual machine and turns that box into the single point through which your whole network reaches the internet: firewall, filtering, VPN and reporting in one web-managed rack of apps.
Honest expectation before you start: the platform download is free, a solid set of core apps stays free forever, and every paid app unlocks for a 14-day trial so you can test before any subscription decision. What is free and what is paid is covered frankly in the later pages of this set — no app is secretly paywalled mid-setup.
There is no direct public download link to guess. The documented route is:
ISO image for physical hardware or an OVA virtual appliance for VMware or a similar hypervisorOnly download from Arista's own portal. Firewall images from file-sharing sites are a classic malware delivery trick, and a gateway is the worst possible machine to compromise.
A gateway sits between two networks, so the machine needs at least two network interfaces: one facing the internet (External/WAN) and one facing your office (Internal/LAN). A spare desktop with a second PCI or PCIe network card added is the classic build. The installer erases the entire hard disk of the target machine — this box becomes a dedicated appliance, not a dual-purpose PC.
Sizing depends honestly on how many users sit behind it and which heavy apps (virus scanning, SSL inspection) you plan to run; the hardware page in this set explains the reasoning. Whatever you choose, put the box plus your modem and switch on a UPS — a gateway that dies in a power cut takes the whole office offline.
Now the one real design decision: Router mode makes NG Firewall your gateway — it takes the public connection, hands out DHCP addresses and does NAT for the office. Bridge mode keeps your existing router in charge and slips NG Firewall transparently between the router and the switch, filtering everything without changing a single IP address. New installs usually choose router mode; bridge mode is the low-risk way to add filtering to a network you cannot re-address. The mode page in this set compares them properly.
Enter the internet details your ISP gave you (DHCP, static or PPPoE), then run the connectivity test the wizard offers. Do not continue past a failed test — every later symptom looks random until basic internet through the box is proven.
The admin interface is a rack: each app is a tile you switch on, and traffic flows through the tiles in order. On day one, enable the free core that needs no subscription: Firewall, Intrusion Prevention, Phish Blocker, Ad Blocker and Reports. If you run guest Wi-Fi, add Captive Portal. Leave the heavy paid apps for the trial page of this set — turning everything on at once is how new admins block the boss's favourite site and lose trust in the box.
Change one thing at a time, and after each change open a few normal websites from a client PC. A gateway mistake is instantly visible to everyone, which is also its advantage: errors announce themselves in seconds, not weeks.
That is a complete, honest day-one gateway: installed in order, filtering the dangerous basics for free, registered, updated and backed up. The rest of this set covers each decision in depth.
The complete installation — download, wizard, interface setup and first configuration — shown live on a real machine, step by step.
▶️ Watch Full VideoYes. Arista Networks acquired Untangle in 2022 and renamed Untangle NG Firewall to Arista Edge Threat Management (ETM) NG Firewall. The rack-style interface, the apps and the install flow carried over, and current releases are in the 17.x series.
The platform and a core set of apps are free: Firewall, Intrusion Prevention, Phish Blocker, Ad Blocker, Captive Portal, OpenVPN and Reports, plus lighter monitor versions of a few filtering apps. The full versions of apps like Web Filter, SSL Inspector, Policy Manager and WAN Failover are subscription apps. Every app includes a 14-day free trial, and when a trial ends the paid app switches off — the gateway itself keeps routing.
A normal PC works if it has two network interfaces — most people add one extra network card to a spare desktop. The installer wipes the disk completely, so the machine becomes a dedicated gateway. It also runs well as a virtual machine using the OVA download, which is the easiest way to evaluate it.