> Mark Andrews wrote: > >> Hello Ray , > >> > >> On Wed, 12 Dec 2007, Ray Pelletier wrote: > >> > >>> Will all be changed to the following: > >>> > >>> NS4.AMSL.COM 64.170.98.30 > >>> NS5.AMSL.COM 64.170.98.31 > >>> NS6.AMSL.COM 2001:5c0:9758::1:1 > >>> > >> Fmi , Are the preceding name servers physically diverse ? > >> Tia , Jiml > >> > > > > There has to be common failure points with NS4.AMSL.COM > > and NS5.AMSL.COM. Think route announcements. > > > Well, yes, of course. > > The question that is more critical is, are there any elements which > aren't common failure points? For them to meet physical diversity requirement there would been to be /32's in the IRP. I suspect you will find that they are just two boxes on the same switch. > If the two IPs are on one physical server, there's very little that > could fail without taking down both instances. > (E.g. single disk failure, memory failure, NIC, crash/reboot, etc.) > > If the two IPs were on different subnets, there would be an expectation > of physical diversity. > However, the same subnet makes this less certain, thus the OP's question. > > Brian You need both physical (power, hardware, location) and operational (different global prefixes, preferably different AS's) diversity for reliable DNS. It's clear from the infomation above that the later is not being met. Mark > _______________________________________________ > Ietf mailing list > Ietf@xxxxxxxx > https://www1.ietf.org/mailman/listinfo/ietf -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: Mark_Andrews@xxxxxxx _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf