Routing Protocols and General Router Features : Routing Information Protocol (RIPv1 and RIPv2) , Layer 2 Tunneling Protocol (L2TP) , Cisco Express Forwarding (CEF) Port Address Translation (PAT) , RFC 1483/2684 , Point-to-Point Protocol over ATM (PPoA) (DSL models only) , PPP over Ethernet (PPPoE) , 802.1d Spanning Tree Protocol (STP) , Dynamic Host Control Protocol (DHCP) server/relay/client , Access control lists (ACLs) , Generic routing encapsulation (GRE) , Dynamic DNS Support for Cisco IOS
Security Features : Stateful Inspection Firewall , Bridging firewall (Cisco 871 only) , NAT transparency , Firewall support for skinny clients , Hardware-accelerated 3DES for IPSec , Hardware-accelerated AES for IPSec , Cisco Easy VPN Client and Server , IPSec 3DES termination/initiation , IPSec passthrough , Point-to-Point Tunneling Protocol (PPTP) passthrough , L2TP passthrough , 802.1 , Secure HTTP (HTTPS), FTP, and Telnet authentication proxies , 10 VPN Tunnels , Advanced Application Inspection and Control , E-mail Inspection Engine , No Service Password Recovery , HTTP Inspection Engine , System Logging–EAL4 Certification Enhancements , Easy VPN Remote Web Based Activation