On Thu, Dec 26, 2024 at 04:53:51AM -0500, Darren Ankney wrote: ! Hi, ! ! It seems to me that the HTTPS/SVCB records describe where and how a ! service is available (could be several IPv4 and IPv6 addresses as well ! as several ports). It does nothing to select how a client might ! connect to the service other than by providing a hierarchy of ! importance for each.
Yes, that's how I understand it: HTTPS/SVCB describes physics from the server side as the server admin perceives them, ip6addrctl and getaddrinfo describe physics from the client side as the client admin perceives them. The most simple use for RFC3484 is to specify whether some system would prefer ipv4 or v6. But it can do more, it can specify which client addresses match to which server addresses for arbitrary subnets, and thereby provide a preference for client AND server addresses. So you can now get preferrable server addresses from the client configuration (based on client side physics), and you can get preferrable server addresses from HTTPS (based on server side physics). More obscurely, you're not the one who decides which of these are to be used; that would rather be some browser coder. I've not completely read RFC3484 (just the ! abstract and introduction) but it seems that this might describe some ! selection parameters that a client might consider in addition to other ! factors when deciding which of the available service addresses to ! connect to. Ideally it would. In practice, on my Berkeley/FreeBSD machines, getaddrinfo provides the results of that selection. getaddrinfo may or may not ask DNS in the process, depending on nsswitch.conf. Then, as far as I understand the HTTPS RR, it is designed to short-circuit this procedure and have the application client directly query the HTTPS RR, in order to benefit by faster startup, and probably ignoring any preference settings from ip6addrctl. I don't yet know how this will work out in practice, but it seems to me there is some potential for unexpected behaviour. cheerio, PMc -- Visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information. bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
