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).
Sorry for being imprecise. Most of talk in IPv6 is about dual-stack so i adopted it without thinking twice about the technical details...
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.
From what i can see i don't want "smtp_host_lookup=native" for potential side-effects, but do i get it right that it is still unsure if the lookup is done in parallel or not when using "native"?
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.
So it is suspected to change some day, but as of now dependant on the OS/nsswitch.conf used?
Many Thanks Andreas
smime.p7s
Description: S/MIME Cryptographic Signature
