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Re: Operating Postfix with IPv6 (dual-stack)

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  • Wietse Venema
    ... 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
    Message 1 of 12 , Feb 1, 2011
      lst_hoe02@...:
      > Zitat von Wietse Venema <wietse@...>:
      >
      > > lst_hoe02@...:
      > >> 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
    • Wietse Venema
      ... Fixed. Grumble. Another to hours of analysis, implementation, test, documentation, and review. Wietse
      Message 2 of 12 , Feb 1, 2011
        Wietse Venema:
        > > >> 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.

        Fixed. Grumble. Another to hours of analysis, implementation, test,
        documentation, and review.

        Wietse
      • lst_hoe02@kwsoft.de
        ... Sorry, i did not want to bother you. My only intention was to prevent that something maybe valuable for performance might get lost. Many Thanks Andreas
        Message 3 of 12 , Feb 1, 2011
          Zitat von Wietse Venema <wietse@...>:

          > Wietse Venema:
          >> > >> 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.
          >
          > Fixed. Grumble. Another to hours of analysis, implementation, test,
          > documentation, and review.
          >
          > Wietse

          Sorry, i did not want to bother you. My only intention was to prevent
          that something maybe valuable for performance might get lost.

          Many Thanks

          Andreas
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