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LibrariesinsideNetworking basics

Updated Mar 2025

DNS

DNS stands for Domain Name Systemexternal_link, which is a form of domain name resolution.

DNS maps static and easily human readable textual (rather than numerical) names to IP addresses. A domain name server resolves the text domain name to the appropriate IP address. For example, entering "ping www.freertos.orgexternal_link" in the command console of a desktop computer will show a ping request being sent to the IP address 195.8.66.1 (at the time of writing - the IP address may change) because a DNS server resolved the string "www.freertos.orgexternal_link" to the IP address 195.8.66.1.

If ipconfigUSE_DNS is set to 1 in FreeRTOSIPConfig.h then the FreeRTOS-Plus-TCP API function FreeRTOS_gethostbyname() can be used to resolve a text name to an IP address.

Like the IP address of the node running FreeRTOS-Plus-TCP, the IP address of a domain name server can be configured either statically as a parameter to FreeRTOS_FillEndPoint(), or FreeRTOS_FillEndPoint_IPv6, or dynamically from a DHCP server.