The Zy XEL SBG3300-N series applies ACL rules, Stateful Packet Inspection (SPI), Denial of Service (Dos) & DDo S features for first-line defense against hackers, network intruders & other harmful threats. A configurable DMZ provides more flexible accessibility while preventing external attacks on confidential databases. The SBG3300-N series in addition features IPSec VPN which empowers companies to provide secure connections to branch offices, partners, road warriors & telecommuters. They can use L2TP or PPTP VPN to safely access corporate networks without having to install VPN software.