Here is a Demo that uses SNTP (Simple Network Time Protocol) to Sync and Set the time of the on-board Spinneret RTC (Real Time Clock). The W5100 is accessed in Indirect mode to open a socket in UDP mode to retrieve the SNTP data. The RTC is then set to the SNTP time and displayed using the PST (Parallax Serial Terminal)
Note2: A previous version used the W5100 in SPI mode, this version uses Indirect/Parallel mode. Not that it matters much for setting the RTC, I just thought it would be easier to transition into an HTML Web application already using the Indirect driver without loading another object.