[Retransmitting from correct e-mail address. -Brad] At 3:57 PM +0100 2004-07-28, David Malone wrote: > Ntpd has some issues in this area. It will always try the first > address returned by getaddrinfo and doesn't fall back to other > addresses if things don't work out. This means if you don't have > IPv6 connectivity, but your server does have an AAAA record, then > you probably won't be able to talk NTP to the server. The fix is > to change ntp.conf to say "server -4 server.name" rather than just > "server server.name". If this were true, then pool.ntp.org would be totally and completely useless. If the initial connection attempt fails or times out, the next IP address in sequence should be used. However, I don't know how the switch-over from IPv6 to IPv4 works. Once ntpd has latched onto a particular number, it won't use any others. Nor will it re-resolve the name into IP addresses, which makes a DNS rotor like pool.ntp.org somewhat less useful. What I'd like to see happen is to have ntpd latch onto all the advertised IP addresses for a given server, and at least contact all of them. If they really are different, then they should be used separately -- kind of like the OpenNTPd "servers" directive. > (The same problem exists with servers with multiple IPv4 addresses, > some of which are unreachable, it's just less obvious...) So far as I know, we're not doing anything unusual with regards to resolving IP addresses or switching from one advertised address to the next. If you've got IP stack problems, that's an issue we may not be able to help with. -- ====================================================================== Brad Knowles, <brad_at_stop.mail-abuse.org> "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." -Benjamin Franklin, Historical Review of Pennsylvania.Received on Wed Jul 28 2004 - 19:03:22 UTC
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