Lectures notes for 2010 - KTH
Lectures notes for 2010 - KTH Lectures notes for 2010 - KTH
DNS Message format 0 16 31 Identification Number of Questions Numer of authority Question section … Answer section … Additional Information section … Parameters Number of Answers Number of Additional Bit or Parameter field Meaning 0 Operation: 0=Query, 1=Response 1-4 Query type: 0=standard, 1=Inverse 5 Set if answer is authoritative 6 Set if answer is truncate 7 Set if answer is desired 8 Set if answer is available 9-11 reserved 12-15 Response Type: 0=No error, 1=Format error in query, 2=Server failure, 3=Name does not exist Maguire DNS Message format 4: 46 of 74 maguire@kth.se 2010.03.21 Internetworking/Internetteknik
(see Stevens, Vol. 1, figure 14.2, pg. 189) Domain com edu gov int mil net org arpa ae … se zw Internet’s top level domains Description commercial organizations educational organizations other U.S. government organizations (see RFC 1811 for policies) international organizations U.S. Military networks other organizations special domain for address to name mappings, e.g., 5.215.237.130.in-addr.arpa United Arab Emerates Sweden Zimbabwe Lots of interest in having subdomains of “com” ♦ companies registering product names, etc. - in some cases asking for 10s of addresses ♦ who gets to use a given name? problems with registered trade marks, who registered the name first, … [How much is a name worth?] Maguire Internet’s top level domains 4: 47 of 74 maguire@kth.se 2010.03.21 Internetworking/Internetteknik
- Page 227 and 228: On a HP-UX 11.0 machine: ping -ov w
- Page 229 and 230: Useful Tool: Traceroute Programs De
- Page 231 and 232: This lecture we have discussed: •
- Page 233 and 234: IK1550 Internetworking/Internettekn
- Page 235 and 236: Transport layer protocols The trans
- Page 237 and 238: User Datagram Protocol (UDP) • Da
- Page 239 and 240: UDP Checksum and Pseudo-Header •
- Page 241 and 242: Port numbers in three groups Range
- Page 243 and 244: Fragmentation Required If datagram
- Page 245 and 246: • on a BSDI system: • each of t
- Page 247 and 248: With an even larger UDP packet I re
- Page 249 and 250: Datagram truncation What if the app
- Page 251 and 252: Learning about Socket programming F
- Page 253 and 254: UDP server design Stevens, Vol, 1,
- Page 255 and 256: Changed the client Changing the fol
- Page 257 and 258: if (!(proto = getprotobyname("raw")
- Page 259 and 260: ICMP Source Quench Error Since UDP
- Page 261 and 262: No error control Since UDP has no e
- Page 263 and 264: BOOTP continued When a request is s
- Page 265 and 266: DHCP: Dynamic Host Configuration Pr
- Page 267 and 268: • Message - used by a server to p
- Page 269 and 270: DHCP’s importance • allows reus
- Page 271 and 272: Example of dhcpd.conf ### Managed b
- Page 273 and 274: Trivial File Transfer Procotol (TFT
- Page 275 and 276: Mapping names to IP addresses Host
- Page 277: Zones A zone is a subtree of the DN
- Page 281 and 282: Domain registrars Internet Corporat
- Page 283 and 284: Resource Records (RR) See Stevens,
- Page 285 and 286: Network names Conventions: • it.k
- Page 287 and 288: Example: $ORIGIN it.kth.se. @ 1D IN
- Page 289 and 290: How to give your host a name? Host
- Page 291 and 292: Configuring DNS • Configuring the
- Page 293 and 294: Load leveling [1] For example, f.ro
- Page 295 and 296: Where is f.root-servers.net ? trace
- Page 297 and 298: Dynamic Domain Name System (DDNS) R
- Page 299 and 300: Attacks upon DNS • Denial of serv
- Page 301 and 302: DNS performance - top 100 From www.
- Page 303 and 304: Web performance - continued Using P
- Page 305 and 306: This lecture we have discussed: •
- Page 307 and 308: IK1550 Internetworking/Internettekn
- Page 309 and 310: Transport layer protocols • User
- Page 311 and 312: Applications which use TCP Lots of
- Page 313 and 314: TCP header continued Reliability is
- Page 315 and 316: time client SYN, seq=x SYN, seq=y,
- Page 317 and 318: client active close ACKs from clien
- Page 319 and 320: Maximum Segment Size • The Maximu
- Page 321 and 322: Window size Increasing window size
- Page 323 and 324: Silly Window Syndrome If receiver a
- Page 325 and 326: Disabling the Nagle Algorithm But s
- Page 327 and 328: Resulting bulk data flow Every segm
DNS Message <strong>for</strong>mat<br />
0 16 31<br />
Identification<br />
Number of Questions<br />
Numer of authority<br />
Question section<br />
…<br />
Answer section<br />
…<br />
Additional In<strong>for</strong>mation section<br />
…<br />
Parameters<br />
Number of Answers<br />
Number of Additional<br />
Bit or Parameter field<br />
Meaning<br />
0 Operation: 0=Query, 1=Response<br />
1-4 Query type: 0=standard, 1=Inverse<br />
5 Set if answer is authoritative<br />
6 Set if answer is truncate<br />
7 Set if answer is desired<br />
8 Set if answer is available<br />
9-11 reserved<br />
12-15 Response Type: 0=No error, 1=Format error in query, 2=Server failure,<br />
3=Name does not exist<br />
Maguire DNS Message <strong>for</strong>mat 4: 46 of 74<br />
maguire@kth.se <strong>2010</strong>.03.21 Internetworking/Internetteknik
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