From 597feb5947b10d5921b6ca2fc3fe39dc1d481ad4 Mon Sep 17 00:00:00 2001 From: Ken Raeburn Date: Mon, 3 Jan 2005 20:27:16 +0000 Subject: [PATCH] * implementor.texinfo (Host Address Lookup): Document Mac OS X issues git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@16989 dc483132-0cff-0310-8789-dd5450dbe970 --- doc/ChangeLog | 5 +++++ doc/implementor.texinfo | 19 +++++++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/doc/ChangeLog b/doc/ChangeLog index 46f458519..6b2121d46 100644 --- a/doc/ChangeLog +++ b/doc/ChangeLog @@ -1,3 +1,8 @@ +2005-01-03 Ken Raeburn + + * implementor.texinfo (Host Address Lookup): Document Mac OS X + issues. + 2004-11-19 Tom Yu * build.texinfo (Solaris 9): Document Solaris patches for pty diff --git a/doc/implementor.texinfo b/doc/implementor.texinfo index d9e00a66b..660967620 100644 --- a/doc/implementor.texinfo +++ b/doc/implementor.texinfo @@ -395,6 +395,25 @@ is, both of which are wrong. No known bugs here, but as of IRIX 6.5.7, the version we're using at MIT, these functions had not been implemented. +@item Mac OS X +Two problems have been found with @code{getaddrinfo} on Mac OS X, at +least under version 10.3. First, while @code{gethostbyname} data is +cached to make multiple lookups of the same name (@i{e.g.}, by +different parts of the code that need to know about the same server +host), @code{getaddrinfo} results are not cached, so multiple queries +mean multiple DNS requests, which means more delays if the DNS servers +are not close by and fast to respond. We've implemented a cache of +our own to work around this, though it only applies to multiple +lookups in a short period of time within the same application process, +and it's only implemented for the Mac at the moment. + +Second, the Mac libraries will generate a DNS SRV RR query; as far as +I [Ken] can tell this is a bug, but Apple seems to consider it a +feature. (Call @code{getaddrinfo("example.com", "telnet", ...)} and +you get a SRV record query, but the spec on SRV records says you must +not use them unless the specification for the service in question says +to.) Yet more network traffic for each name to look up. + @item NetBSD As of NetBSD 1.5, this function is not thread-safe. In 1.5X (intermediate code snapshot between 1.5 and 1.6 releases), the -- 2.26.2