U

UA ( user agents ), 57

UDP (User Datagram Protocol), 43, 390

UDP flooding attacks

DNS servers, 146

overview, 132

SIP phones, 414419

SIP proxies, 393395

UDP packets, 137

UDP ports, 4347, 265287

UDP scans , 35, 4447, 265287

udpflood tool, 132, 296308, 393395, 414418

u-law audio, 195, 471475

Uniform Resource Indicator (URI), 5657

URG flag, 39

URI (Uniform Resource Indicator), 5657

user agents (UA), 57

User Datagram Protocol. See UDP

user support forums, 1920

usernames

INVITE, 7883

OPTIONS, 8490

REGISTER, 7478

SIP, 7395

users. See people