From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_MSPIKE_H2 autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 6580 invoked from network); 11 Jan 2023 15:54:12 -0000 Received: from second.openwall.net (193.110.157.125) by inbox.vuxu.org with ESMTPUTF8; 11 Jan 2023 15:54:12 -0000 Received: (qmail 3408 invoked by uid 550); 11 Jan 2023 15:54:09 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 3373 invoked from network); 11 Jan 2023 15:54:08 -0000 From: "Laurent Bercot" To: musl@lists.openwall.com Cc: liudongxu , "Yulu(Brooklyn,RTOS)" , Nixiaoming , Wangxu , qiuguorui , "wangyunhe (A)" Date: Wed, 11 Jan 2023 15:53:57 +0000 Message-Id: In-Reply-To: <3a82362e2ce04f049042145c986f6da6@huawei.com> References: <3a82362e2ce04f049042145c986f6da6@huawei.com> User-Agent: eM_Client/9.2.1222.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable Subject: Re: [musl] MAXNS should be increased >It is not advisable to use localhost as a DNS server in embedded devices.= It requires a resident process, which consumes many memory and bandwidth. >We only provide devices, not servers. Servers are provided by carriers. We = cannot write a build-in special servers on resolv.conf. That is, unfortunately, a common misconception - but a misconception nonetheless, and if your aim is to provide quality devices that will adequately serve your users, it would probably be a good idea to understand the protocols you're implementing, to understand simple orders of magnitude wrt resources used by software, and to follow correct practices that won't give incoherent results. A caching resolver (which you're calling "server", but DNS servers are an entirely different thing) can be very small, if chosen appropriately. The one I use on all my devices consumes 324 kB plus 2 MB that I choose to allocate as a cache (in order to save bandwidth). As another poster said, it could go as low as 160 kB. Resident processes are not an issue with good system engineering practices: they can be made reliable, and with proper choice of=20 software, they can use a pretty tiny amount of resources. If you wish, you can even configure your caching resolver to forward queries to the carrier's resolvers in all cases, ensuring your devices don't even have to perform the burden of DNS resolution themselves. I realize these basics of systems engineering may not be common knowledge to a company that is only [checks notes] the second largest telecommunication equipment manufacturer in the world. Since this is my area of expertise, I would be happy to help you on that subject. Please contact me privately on the listed e-mail address for business proposals. -- Laurent