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Re: dns and software, was Re: Reliable Cloud host ?
From: Jimmy Hess <mysidia () gmail com>
Date: Thu, 1 Mar 2012 00:15:54 -0600
On Mon, Feb 27, 2012 at 10:57 PM, Matt Addison <matt.addison () lists evilgeni us> wrote:
gai/gni do not return TTL values on any platforms I'm aware of, the only way to get TTL currently is to use a non standard resolver (e.g. lwres). The issue is application developers not calling gai every time
GAI/GNI do not return TTL values, but this should not be a problem. If they were to return anything, it should not be a TTL, but a time() value, after which the result may no longer be used. One way to achieve that would be for GAI to return an opaque structure that contained the IP and such a value, in a manner consumable by the sockets API, and adjust connect() to return an error if passed a structure containing a ' returned time + TTL' in the past. TTL values are a DNS resolver function; the application consuming the sockets API should not be concerned about details of the DNS protocol. All the application developer should need to know is that you invoke GAI/GNI and wait for a response. Once you have that response, it is permissible to use the value immediately, but you may not store or re-use that value for more than a few seconds. If you require that value again later, then you invoke GAI/GNI again; any caching details are the concern of the resolver library developer who has implemented GAI/GNI. -- -JH
Current thread:
- Re: dns and software, was Re: Reliable Cloud host ?, (continued)
- Re: dns and software, was Re: Reliable Cloud host ? Mark Andrews (Feb 28)
- Re: dns and software, was Re: Reliable Cloud host ? William Herrin (Feb 28)
- Re: dns and software, was Re: Reliable Cloud host ? Mark Andrews (Feb 28)
- Re: dns and software, was Re: Reliable Cloud host ? Joe Greco (Feb 29)
- Re: dns and software, was Re: Reliable Cloud host ? William Herrin (Feb 29)
- Re: dns and software, was Re: Reliable Cloud host ? Owen DeLong (Feb 29)
- Re: dns and software, was Re: Reliable Cloud host ? Robert Hajime Lanning (Feb 29)
- Re: dns and software, was Re: Reliable Cloud host ? James M Keller (Feb 29)
- Re: dns and software, was Re: Reliable Cloud host ? Joe Greco (Feb 29)
- Re: dns and software, was Re: Reliable Cloud host ? William Herrin (Feb 29)
- Re: dns and software, was Re: Reliable Cloud host ? Jimmy Hess (Feb 29)
- Re: dns and software, was Re: Reliable Cloud host ? Mark Andrews (Feb 27)
- dns and software, was Re: Reliable Cloud host ? david raistrick (Feb 27)
- Re: Reliable Cloud host ? George Herbert (Feb 27)
- Re: Reliable Cloud host ? Paul Graydon (Feb 27)
- Re: Reliable Cloud host ? William Herrin (Feb 27)
- Re: Reliable Cloud host ? George Herbert (Feb 27)
- Re: Reliable Cloud host ? Jimmy Hess (Feb 29)
- RE: Reliable Cloud host ? Jason Gurtz (Feb 27)