rockwallaby:
Ja, I found using the NTP time server was already giving me some hic-cups recently and looked to use another IP.
Maybe there needs to be some information regarding this in the documentation for the NTP client.
Maybe a hint on how or where to look for suitable NTP servers.
Presumably it needs to do a real domain lookup instead of hard-coding the IP address. The DnsWebClient (http://arduino.cc/en/Tutorial/DnsWebClient) contains code that uses the name lookup service for TCP, but I didn't see any support for doing a DNS query via UDP.
It is rather unfriendly that libraries like this use static IP addresses. Using the domain name service allows the NIST (or other organizations) to use round robin scheduling to distribute the load among servers.