lst_ho...@kwsoft.de:
> Zitat von Wietse Venema <wie...@porcupine.org>:
>
> > lst_ho...@kwsoft.de:
> >> Hello
> >>
> >> we are on the way to IPv6 and some question arise about Postfix IPv6
> >> behaviour in dual stack setup.
> >
> > You mean dual-protocol. Unlike some versions of Linux, there exist
> > systems that have a single unified TCP/IP stack implementation (the
> > protocols have a fair amount of behavior in common).
> >
> >> 1.) Do the lookups for AAAA when resolving MX records occur in
> >> parallel to A queries, or is some additional latency expected due to
> >> the fact that many AAAA queries fail by timeout and others resolving
> >> errors?
> >
> > With smtp_host_lookup=dns, all SMTP client lookups are sequential.
> > With smtp_host_lookup=native (or dns,native) Postfix in dual-protocol
> > mode will invoke getaddrinfo() with hints.ai_family=PF_UNSPEC.
> > The internals of getaddrinfo() are system dependent.
> >
> >> 2.) Do AAAA/ip6.arpa lookup occur on client connects from IPv4
> >> addresses or only when a client connects by IPv6 (name/reverse lookups)?
> >
> > The Postfix SMTP server's FCRDNS lookups use the getnameinfo() and
> > getaddrinfo() system library functions. In dual-protocol mode,
> > Postfix invokes getaddrinfo() with hints.ai_family=PF_UNSPEC; it
> > would be smarter to pass the client's address family instead.
> >
> > Wietse
>
> Is the last point still on todo list or considered worth to be
> included in the future?
It is not a high priority. Moreover, this means ripping up a
low-level API, so it would take longer. I'm still fixing code
that was merged into Postfix 9 years ago.
Wietse
