On 5/28/12, David Conrad <drc@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