Network Perimeter Security: Building Defense In-Depth

LAN routing protocols, 95–96

Layer 1, See Physical layer

Layer 2, See Data-link layer

Layer 2 Forwarding (L2F), 299

Layer 2 Tunneling Protocol (L2TP), 299–305

access concentrator (LAC), 300

considerations as VPN solution, 303–304

encapsulation capability, 303

header fields, 301–302

IPSec and encryption protocol, 300, 302–303, 305

L2TPv3, 304–305

MPLS and, 304

network server (LNS), 300

versions, 299–300

Layer 2 VPNs, 280–283

Layer 2.5 technology (MPLS), 284

Layer 3, See Internet Protocol; Network layer

LDAP, 180

Least privilege, 150

Liability issues, 10–12

Lightweight Directory Access Protocol (LDAP), 180

Link state routing protocols, 96

Linux IPchains firewall software, 238–239

Load balancing, 231–232

intrusion detection systems and, 263

Logging, 152–154

firewall configuration, 219

incident response, 374

timestamping, 153, 169–170

Lucifer, 127