On 16/04/2012 09:08, Jozsef Kadlecsik wrote:
Hostname and IP address are both supported as input and resolved
internally by getaddrinfo. That can generate DNS lookups, depeding on the
resolver library. What kind of system do you use, with which
resolver/libc version?
Thanks so much for replying!
This is a uclibc 0.9.33.1 system, x86. Resolver chain is /etc/hosts,
then dns. Local dnsmasq is installed.
I can very clearly observe that on something like "ipset add", if I add
something that isn't quite an IP address then it generates a name
lookup. What I'm confused by is why the reverse ip lookup for the ip
address? I have traced it back I think to the parser.c code, but I
concede I'm stuck understanding even what is generating the lookup? You
mention resolver, so presumably it's a side effect of some other call,
but could you spare a minute to explain the trigger please? (just
interested in the background in case it occurs elsewhere?)
I could suppress DNS lookups with the price of calling twice getaddrinfo.
You are presumably giving me a clue as the source here!
It would not appear to be a significant performance decrease for the
normal situation to call twice? Given the outside edge case of 1+ min
delays I'm definitely interested in such a change?
Is there any chance of a tentative patch or at least a stronger hint at
what I should change in order that I could deploy something quite
imminently? Its become a bit of a blocker here... Obviously I'm asking
with as much icing as possible and a huge cherry on top...
Thanks Jozsef
Ed W
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