答复: location of NS choosing algorithm
wanrunxia at aliyun.com
Fri Nov 7 01:50:34 UTC 2014
Thanks! That's really helped a lot!
发件人: Mukund Sivaraman [mailto:muks at isc.org]
发送时间: 2014年11月5日 19:42
抄送: bind-workers at lists.isc.org
主题: Re: location of NS choosing algorithm
On Wed, Nov 05, 2014 at 05:50:54PM +0800, RunxiaWan wrote:
> Hi everyone,
> I want to know the implementation of NS selection algorithm in BIND
> Does anyone can help me to locate the function in the source of BIND9.9.5.
> where it is? The function name?
Various things influence this. You'll find part of this in lib/dns/resolver.
c.. part (the SRTT arithmetic) is in lib/dns/adb.c.
If you want a description of SRTT in general, see something like RFC793 that
mentions it, though, in the context of TCP. BIND uses ALPHA=0.7. BIND also
ages SRTT of namesevers that it doesn't update SRTT for by (old_srtt/512).
There is an old nameserver selection method (SRTT part) described in the
following document, but it isn't exactly what happens in BIND anymore:
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