Date: Fri, 09 Sep 2005 00:31:30 +0900 From: Hajimu UMEMOTO <ume@FreeBSD.org> To: Doug Barton <dougb@FreeBSD.org> Cc: arch@FreeBSD.org Subject: Re: [CFR] reflect resolv.conf update to running application Message-ID: <yge7jdrshil.wl%ume@mahoroba.org> In-Reply-To: <430FCAF5.90701@FreeBSD.org> References: <ygefyt4yiaz.wl%ume@mahoroba.org> <430FCAF5.90701@FreeBSD.org>
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Hi, >>>>> On Fri, 26 Aug 2005 19:07:49 -0700 >>>>> Doug Barton <dougb@FreeBSD.org> said: dougb> I've been following this thread with interest, and while I applaud the dougb> effort that's gone into this I'm not sure it has a very high cost/benefit dougb> ratio for the majority of FreeBSD systems. This would potentially be useful dougb> for mobile systems that will often be moved into different networks, but dougb> frankly I don't see a benefit for the vast majority of systems that will dougb> have the same resolv.conf file for weeks, months, or years. I'm also dougb> thinking of various types of high performance systems that actually do dougb> thousands of DNS queries a minute. While a stat() call in the resolver path dougb> for every query might not be noticeable on a "typical" system, they would dougb> add up on systems that are already being stressed. Yup, there might be no benefit for non-mobile users. However, I believe it is still useful for mobile users. So, I changed to look a kernel environment variable. If resolver_reread_conf is set, the feature will be activated. You can find my new patches from: http://www.imasy.or.jp/~ume/FreeBSD/resolver-check-resolv.conf-20050908.diff http://www.imasy.or.jp/~ume/FreeBSD/dhclient-script-renew-20050908.diff dougb> Personally, I would much rather we add some method of "HUPing" the resolver dougb> to re-read resolv.conf. That way we could add that command to dougb> dhclient-script and send it whenever the resolv.conf file is actually dougb> changed. This could also be used by sysadmins for typically "static" systems dougb> instead of having to restart services on those systems. Since a resolver is in each applications, I think it is hard to send a HUP signal to resolvers without having a daemon which does DNS query. Sincerely, -- Hajimu UMEMOTO @ Internet Mutual Aid Society Yokohama, Japan ume@mahoroba.org ume@{,jp.}FreeBSD.org http://www.imasy.org/~ume/
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