Index V

V

Variable-Length Subnet Masks (VLSM), 138

with class B example, 141–45

defined, 138

OSPF support, 192

routing protocols supporting, 150

Vendor management products, 672

Virtual links, 197

Virtual Private Networks (VPNs), 224, 313, 552

address transparency and, 352

architectures, 353–56

connections, 350

dedicated, 352, 356

defined, 349

deployment over Internet, 351

designing, 380–86

design models, 380–81

dial, 351, 353–55

firewall interaction, 382–84

fragmentation, 385

headers, 385

illustrated, 350

issues with, 352–53

management/maintenance and, 353

MPLS-based backbones, 386

overlay model, 380–81

peer model, 381

performance, 384–85

protocol encapsulation and, 352

reliability and, 353

routing, 382

scalability and management, 385–86

security and, 352–53

types of, 351–52

Virtual router, 443

Virtual Router Redundancy Protocol (VRRP), 91, 439, 442–52

address seeding, 447

advertisements, 446

ARP interaction, 448

backup routers, 446

backward compatibility, 451–52

clustering, 442

configuration with LAN and WAN interfaces, 451

configuration with resilience for high-speed server form, 449

convergence speed, 452

defined, 442

definitions, 442–43

duplicate packets and, 452

example design, 448–50

field definitions, 444–45

HSRP vs., 453–54

ICMP echo interaction, 447

ICMP redirects, 447

issues, 450–52

as LAN-based protocol, 443

with load sharing, 514–15

master election process, 445–46

operation, 445–50

packet format, 444–45

routers, 443

routing problems, 450

scalability, 451

topological knowledge, 450

use of, 442

virtual groups, 446

Viruses, 307

defined, 307, 346

protection systems, 346–47

types, 346–47

Vulnerabilities

application/protocol, 308–12

DNS, 310–11

FTP, 309

HTTP, 310

ICMP, 308

IP, 308

operating system, 312

SMTP, 310

SSI, 311

TCP, 308–9

Telnet, 309

TFTP, 310

third-party trust, 312–13

UDP, 308