USG FLEX Firewall

Retail/Branch Office VPN Firewall

The USG FLEX 50 is now part of the Nebula cloud management family with the same easy management interface and streamlined configuration & updates. The network functions and management services are pushed to the cloud and are optimized for managing distributed networks.

Secure Retail/Branch Network

The USG FLEX 50 provides comprehensive VPN connection types including IKEv2, SSL & IPsec VPN. All offer customers secured remote connections. IPsec VPN hardware engine for high-efficiency VPN tunnel. VPN load balance/failover with IKEv2 ensures strong VPN reliability and security for your business.

The USG FLEX 50 is designed specifically for the needs of small business and branch locations, delivering enterprise-class security. Advanced networking and security features like Web Filtering, Security Profile Sync, and SecuReporter improves security by blocking access to malicious or risky websites, along with controlled access with integrated firewall policy for highly granular blocking and filtering, creating a unified security solution for both wired and wireless networks.



Centralized Provisioning from Nebula

With Zero-Touch deployment and simplified centralized management, installation and operation is no longer a hassle. After being registered to a network, the USG FLEX 50 will automatically be discovered when it’s connected, then the preconfigured settings are automatically applied.

The USG FLEX 50 helps customers to comply with regulations by offering log archiving service without the need for additional hardware and software installation.

All from One Place with Ease

From access points, switches, security gateways and firewalls, all Nebula devices are managed through the cloud using an intuitive interface that allows you to configure, manage, and troubleshoot all distributed networks from one single screen without the complexity of remote site access.

Deep Insight Into All Your Devices

Device Insight gives you more visibility of your networks including wired, wireless, BYOD, and IoT devices. You can create access policy with device contextual such as OS version or device category to enforce network segmentation. This reduces the attack surface and prevents threats from spreading. It also helps SMB(s) reduce time spent on investigation. Continuing with our goal of providing our customers with increased visibility, Zyxel SecuReporter gives your organization comprehensive endpoint inventory dashboard.


Comprehensive Web Filtering Service

USG FLEX Firewall delivers enhanced web filtering functionality and security through its powerful combination of both reputation and category-based filtering. The dynamic content categorization analyzes the content of a previously unknown website and domain, then determines if it belongs to an undesirable category including gambling, pornography, games, and many others. A newly added DNS content filter offers a better approach to inspect web access, particularly when the website is deploying ESNI (Encrypted Server Name Indication) where the traditional URL filtering is not applicable to the destination domain.

Analytics Report and Enhanced Insights

USG FLEX 50 dashboard gives user-friendly traffic summary and threat visual statistics. Utilize SecuReporter for further threat analysis with correlation feature design, making it easy to proactively trackback network status to prevent the next threat event. Centralized visibility of network activities for you to easily manage multiple clients.


Hardware Specifications
Wireless standard -
10/100/1000 Mbps RJ-45 ports 4 x LAN/DMZ, 1 x WAN
USB 3.0 ports 1
Console port RJ45
Rack-mountable -
Fanless Yes
System Capacity & Performance*1
SPI firewall throughput(Mbps)*2 350
VPN throughput (Mbps) 90
VPN IMIX Throughput (Mbps)*3 40
IPS throughput (Mbps)*4 -
Anti-Malware throughput (Mbps)*4 -
UTM throughput (Anti-Malware & IPS, Mbps)*4 -
Max. TCP concurrent sessions*5 20,000
Recommended gateway-to-gateway IPsec VPN tunnels 5
Max. concurrent IPsec VPN tunnels*6 10
Concurrent SSL VPN users 5/15
VLAN interface 8
Wireless Specifications
Standard compliance -
Wireless frequency -
Radio -
SSID number -
No. of antenna -
Antenna gain -
Data rate -
Key Features
Security Service
Sandboxing*7 -
Reputation Filter*7 -
IPS*7 -
Application Patrol*7 -
Email Security*7 -
Web Filtering*7 Yes
SecuReporter*7 Yes
Collaborative Detection & Response*7 -
SSL (HTTPS) Inspection -
Geo Enforcer Yes
2-Factor Authentication Yes
Device Insight Yes
Security Profile Synchronize*7 Yes
VPN Features
Microsoft Azure Yes
Amazon VPC Yes
WLAN Management
Default Number of Managed AP -
Recommend max. AP in 1 AP Group -
Secure WiFi Service*7 -
Maximum Number of Tunnel-Mode AP -
Maximum Number of Managed AP -
Management & Connectivity
Nebula Cloud Mode Yes
Nebula Cloud Monitoring Mode Yes
Device HA Pro -
Link Aggregation (LAG) -
Hotspot Management*7 -
Ticket printer support*9/ Support Qty (max.) -
Concurrent devices logins (max.) *7*8 64
Power input 12V DC, 2A max.
Max. power consumption (watt) 12.5
Heat dissipation (BTU/hr) 40.92
Physical Specifications
Item Dimensions (WxDxH)(mm/in.): 216 x 147.3 x 33/8.50 x 5.80 x 1.30
Weight (kg/lb.): 0.88/1.94
Packing Dimensions (WxDxH)(mm/in.): 276 x 185 x 98/10.87 x 7.28 x 3.86
Weight (kg/lb.): 1.41/3.11
Included accessories Power adapter
RJ-45 - RS-232 cable for console connection
Environmental Specifications
Operating Temperature: 0°C to 40°C / 32°F to 104°F
Humidity: 10% to 90% (non-condensing)
Storage Temperature: -40°C to 70°C/-40°F to 158°F
Humidity: 10% to 90%(non-condensing)
MTBF (hr) 655,130
Acoustic noise -
EMC FCC Part 15 (Class B)
CE EMC (Class B)
Safety BSMI


*: This matrix with firmware ZLD5.37 or later.

*1: Actual performance may vary depending on system configuration, network conditions, and activated applications.

*2: Maximum throughput based on RFC 2544 (1,518-byte UDP packets).

*3: VPN throughput measured based on RFC 2544 (1,424-byte UDP packets); IMIX: UDP throughput based on a combination of 64 byte, 512 byte and 1424 byte packet sizes.

*4: Anti-malware (with Express Mode) and IPS throughput measured using the industry standard HTTP performance test (1,460-byte HTTP packets). Testing done with multiple flows.

*5: Maximum sessions measured using the industry standard IXIA IxLoad testing tool.

*6: Including Gateway-to-Gateway and Client-to-Gateway.

*7: With Zyxel service license to enable or extend the feature capacity.

*8: This is the recommended maximum number of concurrent logged-in devices.

*9: With Hotspot Management license support.

*10: USG FLEX 100 rev1 is adopting a new hardware design equipped with 4 x LAN/DMZ, 1 x WAN.


* License subscription fee and permits may vary by country.
* All specifications are subject to change without notice.


More Data Sheet

License and Service

The USG FLEX 50 provides an indispensable feature set to perfectly fit small business requirements as well as to gain essential security services needed to protect against cyberattacks. Nebula Control Center (NCC) offers multiple subscription options to meet customers’ needs. The Nebula Plus/Professional Pack give you peace of mind at more control over your network updates and visibility, or even the most advanced management of cloud networking.



On Premises Feature Included
Nebula Feature Included
Service/Component On Premises Nebula Cloud
Content Filter Pack* Web Filtering
Content Filter Pack* SecuReporter
Content Filter Pack* Security Profile Sync No License Included*3
Content Filter Pack* Network Premium
Nebula Professional Pack Nebula Professional Pack Service No License Included*3
Nebula Plus Pack Nebula Plus Pack Service No License Included*3

*Please contact your local customer service if you can’t use your content filter license with Nebula.


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