HP 635n HP Jetdirect Print Servers - Practical IPv6 Deployment for Printing an - Page 14

• "ping mfp2" • "ping mfp2.example.internal" Depending on the name typed in, two very different name resolutions are carried out by Vista. We talked earlier about single label names and multi-label names. The "ping mfp2" command is where we will start, assuming it is execute on Vista1. In order to illustrate the difference in name resolution between the two commands, let's assume that the user makes a mistake and types in "mfp3" instead of "mfp2" for both commands. Let's look at what happens for "ping mfp3" (Refer back to Figure 2): • Step 0: The ping application, which on Vista is IP Neutral, internally calls getaddrinfo() with the name "mfp3" • Step 1: The resolver checks the DNS cache. "mfp3" not found. • Step 2: The resolver sees that there is a DNS configuration. Taking the name "mfp3", it concatenates ".example.internal." as the primary DNS suffix and asks the DNS server for name resolution information for the A record or IPv4 record. This process will continue as long as there are DNS suffixes available in the configuration. The name "mfp3.example.internal" will return a result code indicating that condition. • Step 3: The resolver checks the LLMNR cache. "mfp3" not found. • Step 4: Vista1 sends an LLMNR Name Query Request packet over IPv6 using a destination IPv6 multicast address of FF02::1:3 first, then Vista1 sends an LLMNR Name Query Request packet over IPv4 using a destination IPv4 multicast address of 224.0.0.252. There is no response since the HP MFP doesn't support LLMNR. • Step 5: Vista1 checks the NetBIOS name cache. "MFP3" is not found. • Step 6: Vista1 checks the WINS server. "MFP3" is not found. • Step 7: Vista1 sends out a NetBIOS broadcast over IPv4. "MFP3" is not found. • Step 8: Not Performed Compare this process to this command executed on the same machine "ping mfp3.example.internal" • Step 0: The ping application, which on Vista is IP Neutral, internally calls getaddrinfo() with the name "mfp3.example.internal" • Step 1: The resolver checks the DNS cache. "mfp3.example.internal" not found. • Step 2: The resolver sees that there is a DNS configuration. The resolver asks the DNS server to resolve the name "mfp3.example.internal" to an IPv4 address (an DNS A record). Since this name doesn't exist, it will return a result code indicating that condition. • Step 3: Not Performed • Step 4: Not Performed • Step 5: Not Performed • Step 6: Not Performed • Step 7: Not Performed • Step 8: Not Performed In the second command, because the user has specified an FQDN, only the DNS server is queried. Vista1 will not try to get the AAAA record because Vista1 only has a Link Local IPv6 address. Since other Link Local IPv6 addresses should not be in DNS and Link Local IPv6 addresses cannot be routed, to ask for an AAAA record would be to simply waste DNS server bandwidth. What if the user had typed "mfp2" correctly? Well, both name resolutions would have gone to Step 2 and succeeded. What if the record wasn't in DNS? Well, the command "ping mfp2" would have been successful because the WINS server would have been tried. However, the command "ping mfp2.example.internal" would have failed because only the DNS server is tried because the user entered an FQDN. This is an important point: "ping mfp2" would have worked but "ping 14