nanog mailing list archives
Re: dns and software, was Re: Reliable Cloud host ?
From: William Herrin <bill () herrin us>
Date: Tue, 28 Feb 2012 08:11:54 -0500
On Tue, Feb 28, 2012 at 12:45 AM, Mark Andrews <marka () isc org> wrote:
getaddrinfo was designed to be extensible as was struct addrinfo. Part of the problem with TTL is not [all] data sources used by getaddrinfo have TTL information.
Hi Mark, By the time getaddrinfo replaced gethostbyname, NIS and similar systems were on their way out. It was reasonably well understood that many if not most of the calls would return information gained from the DNS. Depending on how you look at it, choosing not to propagate TTL knowledge was either a belligerent choice to continue disrespecting the DNS Time To Live or it was fatalistic acceptance that the DNS TTL isn't and would not become functional at the application level. Still works fine deeper in the query system, timing out which server holds the records though.
Additionally for many uses you want to reconnect to the same server rather than the same name.
The SRV record was designed to solve that whole class of problems without damaging the operation of the TTL. No one uses it. It's all really very unfortunate. The recipe for SOHO multihoming, the end of routing table bloat and IP roaming without pivoting off a home base all boils down to two technologies: (1) a layer 4 protocol that can dynamically rebind to the layer 3 IP address the same way IP uses ARP to rebind to a changing ethernet MAC and (2) a DNS TTL that actually works so that the DNS supports finding a connection's current IP address. Regards, Bill Herrin -- William D. Herrin ................ herrin () dirtside com bill () herrin us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
Current thread:
- Re: Reliable Cloud host ?, (continued)
- Re: Reliable Cloud host ? Bobby Mac (Feb 29)
- Re: Reliable Cloud host ? Valdis . Kletnieks (Feb 28)
- dns and software, was Re: Reliable Cloud host ? david raistrick (Feb 27)
- Re: dns and software, was Re: Reliable Cloud host ? William Herrin (Feb 27)
- Re: dns and software, was Re: Reliable Cloud host ? Owen DeLong (Feb 27)
- Re: dns and software, was Re: Reliable Cloud host ? William Herrin (Feb 27)
- Re: dns and software, was Re: Reliable Cloud host ? George Herbert (Feb 27)
- Re: dns and software, was Re: Reliable Cloud host ? Matt Addison (Feb 27)
- Re: dns and software, was Re: Reliable Cloud host ? Mark Andrews (Feb 27)
- Re: dns and software, was Re: Reliable Cloud host ? Owen DeLong (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 ? 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)