This behavior seems fine in lieu of what the client can reasonably be expected to know. My fear is in the case of a pool with 10+ ipv4 AND 10+ ipv6 sources: If I have a single-stack host, will it load a list of [max sources] time sources and THEN determine if they're reachable or will it do initial reach-ability followed by populating [max sources] in the active list based on which hosts responded? I suspect the behavior is the former, putting the overall average number of reachable nodes for a single-stack host at [max sources]/2. This SHOULD be adequate in most cases, but is probably sub-optimal. I'm thinking now about making separate v4 and v6 pools for hosts...
Is that the reason for the pool.ntp.org being ipv4-only and 2.pools.ntp.org having v4 and v6 together? Is there a best practice recommendation for clients in a mixed ipv4/ipv6 single/dual stack environment? Dan ----- Original Message ----- > From: "Dag-Erling Smørgrav" <[email protected]> > To: "Dan Geist" <[email protected]> > Cc: "lst hoe02" <[email protected]>, [email protected] > Sent: Saturday, November 7, 2015 7:11:56 AM > Subject: Re: [Pool] pool IPv4/IPv6 behavior with ntpd > Dan Geist <[email protected]> writes: >> I'm not sure I agree with that behavior (from a client/peer use-case >> perspective). Wouldn't it make more sense to only use the stack that's >> actually available? That's how it works with DNS typically: If >> ghostbyname yields an A and AAAA record, applications don't attempt to >> use the AAAA record if there is no ipv6 stack configured, right? > > There is no reliable way for an application to tell whether IPv6 is > supported. Standard procedure is to use getaddrinfo(), iterate over the > results, try to bind or connect to each address (depending on whether > you're a server or a client) and ignore any failures as long as at least > one address works. > > DES > -- > Dag-Erling Smørgrav - [email protected] -- Dan Geist dan(@)polter.net _______________________________________________ pool mailing list [email protected] http://lists.ntp.org/listinfo/pool
