... to 1 concurrent tunnel. IPSec provides features of auto key (IKE) and manual key, ESP/AH protocols, DES/3DES/AES encryption ... NAT, DHCP, SNTP, TELNET, HTTP, TFTP, PPP, PPPoE, PAP, CHAP, IKE, ISAKMP, ESP, AH, MD5, SHA-1, DES, 3DES, AES, L2TP ...