From owner-freebsd-questions@FreeBSD.ORG Tue Jun 4 03:39:41 2013 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 3964CE1A for ; Tue, 4 Jun 2013 03:39:41 +0000 (UTC) (envelope-from me@staticsafe.ca) Received: from uriel.asininetech.com (uriel.asininetech.com [142.4.209.58]) by mx1.freebsd.org (Postfix) with ESMTP id 0E3E51897 for ; Tue, 4 Jun 2013 03:39:40 +0000 (UTC) Received: from localhost (localhost.localdomain [127.0.0.1]) by uriel.asininetech.com (Postfix) with ESMTP id D76E8E099E; Mon, 3 Jun 2013 23:39:33 -0400 (EDT) X-DKIM: OpenDKIM Filter v2.6.8 uriel.asininetech.com D76E8E099E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=staticsafe.ca; s=2012; t=1370317173; bh=1hnIdUxnvlDiiZZLIqocJ05Z8XQZavtExzBiSLQgx00=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=fkpcyj8oJwujQcxUP2oBDhZPGyFEKufpemvpzmtVQoHah59lQPfZxgL+n/THk6XTQ 29drt5aDsXwPPq3cqbmBD+HW0+EXJBC0FjA78A1e/0yw+/Ns9s/2XUi3wI+0QRemog hPqtDbL2ymA0Kr54UkIxgaAMLuIV6xGOGdDtz2xs= Received: from uriel.asininetech.com ([127.0.0.1]) by localhost (uriel.asininetech.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id sPTpoIhYFvET; Mon, 3 Jun 2013 23:39:33 -0400 (EDT) Received: from uriel.asininetech.com (uriel.asininetech.com [IPv6:2607:5300:60:e3a::1]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by uriel.asininetech.com (Postfix) with ESMTPSA id 0DC94E01A0; Mon, 3 Jun 2013 23:39:33 -0400 (EDT) X-DKIM: OpenDKIM Filter v2.6.8 uriel.asininetech.com 0DC94E01A0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=staticsafe.ca; s=2012; t=1370317173; bh=1hnIdUxnvlDiiZZLIqocJ05Z8XQZavtExzBiSLQgx00=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=fkpcyj8oJwujQcxUP2oBDhZPGyFEKufpemvpzmtVQoHah59lQPfZxgL+n/THk6XTQ 29drt5aDsXwPPq3cqbmBD+HW0+EXJBC0FjA78A1e/0yw+/Ns9s/2XUi3wI+0QRemog hPqtDbL2ymA0Kr54UkIxgaAMLuIV6xGOGdDtz2xs= Date: Mon, 3 Jun 2013 23:39:31 -0400 From: staticsafe To: freebsd-questions@freebsd.org Subject: Re: System Calls that do DNS Message-ID: <20130604033930.GA10393@uriel.asininetech.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 04 Jun 2013 03:39:41 -0000 On Mon, Jun 03, 2013 at 07:57:07PM -0700, Doug Hardie wrote: > I have an unusual situation. A program is doing a DNS lookup and often the IP address has no reverse DNS entries. As a result the program hangs for several timeouts. The call is not being made directly in its code, but is occurring in a system call. There are no specific calls to DNS, its something else doing it. I have been trying to track down which system call is doing it, but without success so far. I have tried syslog calls around each of the system calls I thought might be the culprit, but my guessing is not very good. How can I identify the system call that is calling DNS? If I can find it, I hopefully can find another way to do whatever it does that does not involve a reverse DNS lookup. > > Use truss: http://www.freebsd.org/cgi/man.cgi?query=truss The truss utility traces the system calls called by the specified process or program. -- staticsafe O< ascii ribbon campaign - stop html mail - www.asciiribbon.org Please don't top post - http://goo.gl/YrmAb Don't CC me! I'm subscribed to whatever list I just posted on.