On 5/28/12, David Conrad <d...@virtualized.org> wrote: > On May 28, 2012, at 11:51 AM, Anurag Bhatia wrote: >> I know few registry/registrars >> which do not accept both (or all) name servers of domain name on same >> subnet. They demand at least 1 DNS server should be on different subnet for >> failover reasons (old thoughts). > IMHO appropriately so. The fact that anycast allows for multiple > (potentially) geographically distributed machines to respond to DNS queries > does not remove the value of having multiple prefixes for DNS servers. [snip] It dramatically reduces the value, and meets the basic RFC requirement for geographically distributed DNS servers, although there are still routing issues that will impact all DNS servers to share a prefix It is more important that a domain registrar not refuse to register a domain, or erroneously declare a valid listing invalid.
The purpose of using a registrar is to establish DNS delegation, not to validate your site's redundancy meets the absolute best possible practices for fault tolerance. Ideally certainly should have DNS servers under multiple prefixes -- and it seems a little bit silly to go through all the trouble of implementing a complicated anycast geo. dist scheme, while ignoring a simpler failure mode. It's your choice. It's not appropriately so for a registrar to say anything your choice; thats your network not theirs. By the same token the registrar can't tell you not to alias all 3 IP addresses on different subnets to the same physical server. Again, it's ill-advised, but a "mistake" that has nothing to do with the registrar's network or the registration service. -- -JH
