data links, libpcap library and, 20
database description (DBD) header (OSPF), 66-67
database, for libsf, 118-119
database, for vulnerability scanners and scanning, 259
debugging, 10
decoding, protocol, 195-196
defensive techniques, 5-6, 293-326
demultiplexing, packet sniffing and, 195-196
denial of service (DOS) in attack and penetration techniques for, 257
DES, OpenSSL library functions and, 165
Descry sample program for NIDS, 303-326
design phase of software development, 8
destination port, 91
device initialization, 13-15, 22-33, 75, 341-342
digital signatures, 164, 174-175
Digital Unix, 13
DIX headers, 48
domain name server (DNS), 43, 56, 218, 272-291
dropped packets, 12-13
dump functions, 19-20
dynamic host configuration protocol (DHCP), 55-56