The TL-ER6120 supports multiple VPN protocols including IPsec, PPTP and L2TP in Client/Server mode and can handle pass-through traffic as well. It also features a built-in hardware-based VPN engine allowing the router to support and manage up to 100 LAN-to-LAN/Client-to-LAN IPsec VPN connections. Advanced VPN features include: DES/3DES/AES128/AES192/AES256 encryption, MD5/SHA1 authentication, Manual/IKE key management, and Main/Aggressive negotiation modes.

For defense against external threats, TL-ER6120 features an automatic protection to detect and block Denial of service (DoS) attacks such as TCP/UDP/ICMP Flooding, TCP Scanning, Ping of Death and other related threats. Moreover, this router offers a hardware DMZ port, which allows you to setup public servers without exposing your internal network, to avoid attacks from external threats. For better management of the internal network, TL-ER6120 allows administrators to set rules to block specific web sites and IM/P2P applications with just one-click, and restrict staff to use specific services such as FTP, HTTP and SMTP.

The TL-ER6120 features two WAN ports, allowing the router to satisfy various Internet access requirements through one device. The Intelligent Load Balancing function can distribute data streams according to the bandwidth proportion of every WAN port to raise the utilization rate of multi-line broadband. With IP-based Bandwidth Control and Session Limit functions, network administrators can flexibly manage network bandwidth to optimize bandwidth usage.

Professional lightning protection technology is designed to prevent electrical surges from penetrating the interior of the electrical equipment and is discharged harmlessly into the Earth. This router is designed to prevent lightning up to 4Kv in the well-grounded connection conditions. This feature ensures that networking infrastructure investments remain as safe as possible from one of mother nature's more violent situations.