Another problem with a public NTP server: Poul-Henning Kamp runs an NTP server on the Danish internet exchange DIX. He found out D-link routers all hammer on that NTP server (and lots of others) without any prior agreement. Read his Open Letter to D-Link about their NTP vandalism and Richard Clayton's write-up on how he researched the problem and found the source in the D-Link equipment. NTP was one of the last services that you could run cooperatively and assume your clients would play nice, now with 'home broadband routers' everywhere out in the world who like to keep the right time (and use sloppy-programmed client software to get that time), this trust in cooperative clients has been broken several times. Yes, this looks a lot like the former case with the University of Wisconsin - Madison and Netgear routers. At least, that case was solved with a good fix and an apology from Netgear.