1.2.1.8 DNS Server Module

A step-by-step analysis of the DNS Server is as follows:

• DNS server can be enabled or disabled at run time.
• If the TCP/IP commands module is built in, it contains a "dnss" command that could be used for interfacing with the DNSS module.
• A client sends some query to the DNS Server of the TCP/IP stack for a name resolution.
• The DNS Server of the TCP/IP Stack first checks the configuration value of replyBoardAddr.
  • This Boolean flag is passed to the DNSS module at initialization time.
• If replyBoardAddr is true, the DNS server will reply to the client query with its own board address.
• If replyBoardAddr is false, the DNSS will check its cache for an entry for that name.
  • If a valid entry is found, the reply is sent to the client requesting the info.
  • Otherwise no reply is provided.
• To update the DNSS cache, new entries can be added either using the DNSS API or directly from the console, using the "dnss" command.
• The dnsserv command is used to add, delete and display the DNS server details
• Authoritative Name servers and Addition Name servers are not processed.
• The client may store the answer to the DNS query in it's own cache for future use.