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diff --git a/doc/README.dns b/doc/README.dns new file mode 100644 index 00000000000..deeccd77200 --- /dev/null +++ b/doc/README.dns @@ -0,0 +1,64 @@ +Domain Name System +------------------------------------------- + +The Domain Name System (DNS) is a hierarchical naming system for computers, +services, or any resource participating in the Internet. It associates various +information with domain names assigned to each of the participants. Most +importantly, it translates domain names meaningful to humans into the numerical +(binary) identifiers associated with networking equipment for the purpose of +locating and addressing these devices world-wide. An often used analogy to +explain the Domain Name System is that it serves as the "phone book" for the +Internet by translating human-friendly computer hostnames into IP addresses. +For example, www.example.com translates to 208.77.188.166. + +For more information on DNS - http://en.wikipedia.org/wiki/Domain_Name_System + + + +U-Boot and DNS +------------------------------------------ + +CONFIG_CMD_DNS - controls if the 'dns' command is compiled in. If it is, it + will send name lookups to the dns server (env var 'dnsip') + Turning this option on will about abou 1k to U-Boot's size. + + Example: + +bfin> print dnsip +dnsip=192.168.0.1 + +bfin> dns www.google.com +66.102.1.104 + + By default, dns does nothing except print the IP number on + the default console - which by itself, would be pretty + useless. Adding a third argument to the dns command will + use that as the environment variable to be set. + + Example: + +bfin> print googleip +## Error: "googleip" not defined +bfin> dns www.google.com googleip +64.233.161.104 +bfin> print googleip +googleip=64.233.161.104 +bfin> ping ${googleip} +Using Blackfin EMAC device +host 64.233.161.104 is alive + + In this way, you can lookup, and set many more meaningful + things. + +bfin> sntp +ntpserverip not set +bfin> dns pool.ntp.org ntpserverip +72.18.205.156 +bfin> sntp +Date: 2009-07-18 Time: 4:06:57 + + For some helpful things that can be related to DNS in U-Boot, + look at the top level README for these config options: + CONFIG_CMD_DHCP + CONFIG_BOOTP_DNS + CONFIG_BOOTP_DNS2 |