... L2TP,IPSEC and GRE)(only for VPN version),DHCP server and client,DDNS (dynamic DNS),firewall,NAT and ... filterSupport multi protocols , such as TCP/IP,UDP,ICMP,SMTP,HTTP,POP3,OICQ,TELNET,FTP ,SNMP ,etc.Support ... specifying local and remote IPCan be used as PPP server. Support multi authentication method, such as PAP,CHAP,CHAP ... upgrade firmwareSupport multi OS, such as WINDOWS, LINUX, SCO UNIX etc