Re:Why ALIAS-type DNS Records Break The Internet
by belorn on Wednesday January 08, 2014 @09:17AM
(#7023549)
> If implementing recursion based ALIAS foo.mydomain RRs MUST respect the TTL of bar.otherdomains RRs.
There is only two ways that I can think of. The nameserver could sets foo.mydomain TTL to be the reminder of bar.otherdomains current cached ttl, but it would mean that at some point it could go down as little as 1s long.
Or, the name server could make a new fresh resolving of bar.otherdomains, and forward that as the answer to foo.mydomain with bar.otherdomains TTL intact. However, that would make requests for foo.mydomain quite slow and severely increase the workload for the nameserver.
Given the problem of each of those solutions, its seems the common approach is to simply put a short TTL on foo.mydomain regardless of the TTL on bar.otherdomains, and then pray. Thus this article.
There is only two ways that I can think of. The nameserver could sets foo.mydomain TTL to be the reminder of bar.otherdomains current cached ttl, but it would mean that at some point it could go down as little as 1s long.
Or, the name server could make a new fresh resolving of bar.otherdomains, and forward that as the answer to foo.mydomain with bar.otherdomains TTL intact. However, that would make requests for foo.mydomain quite slow and severely increase the workload for the nameserver.
Given the problem of each of those solutions, its seems the common approach is to simply put a short TTL on foo.mydomain regardless of the TTL on bar.otherdomains, and then pray. Thus this article.