From owner-freebsd-questions@freebsd.org Fri Feb 28 06:25:19 2020 Return-Path: Delivered-To: freebsd-questions@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 2A30725B36C for ; Fri, 28 Feb 2020 06:25:19 +0000 (UTC) (envelope-from dewayne@heuristicsystems.com.au) Received: from hermes.heuristicsystems.com.au (hermes.heuristicsystems.com.au [203.41.22.115]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (2560 bits) client-digest SHA256) (Client CN "hermes.heuristicsystems.com.au", Issuer "Heuristic Systems Type 4 Host CA" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 48TKK91d4bz4NSm for ; Fri, 28 Feb 2020 06:25:16 +0000 (UTC) (envelope-from dewayne@heuristicsystems.com.au) Received: from [10.0.5.3] (noddy.hs [10.0.5.3]) (authenticated bits=0) by hermes.heuristicsystems.com.au (8.15.2/8.15.2) with ESMTPSA id 01S6OaEM042896 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT) for ; Fri, 28 Feb 2020 17:24:36 +1100 (AEDT) (envelope-from dewayne@heuristicsystems.com.au) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=heuristicsystems.com.au; s=hsa; t=1582871076; x=1583475877; bh=pNMbW7HAJkcKU7FSBh0rqe3Oj5+pT0wEMsaYyqVx6NY=; h=Subject:To:From:Message-ID:Date; b=Sc7QEQpv7QCfA+G3swe+ifNhb7BvRrvY8KYJmFM+1KyTFjqNG7rCoMZyJBbF6fbd6 SDi3vGXrP4e1/IZNlTwYT8I+paN9uNuXxBMLpPruVlH5aqnItY/I+e4HZrKQ/x89PC QnWVdac7hgF7+j6ou9AuzHTpuvCCyVA4h/LwfXlb1E6IZ1xZI2ltR X-Authentication-Warning: b3.hs: Host noddy.hs [10.0.5.3] claimed to be [10.0.5.3] Subject: Re: DNS resolution To: freebsd-questions@freebsd.org References: <93893C00-93BD-4C71-943E-8751DF2854FE@mail.sermon-archive.info> From: Dewayne Geraghty Autocrypt: addr=dewayne@heuristicsystems.com.au; prefer-encrypt=mutual; keydata= mQFNBFbOsVMBCgDfvi2PspSwoMEtFhF+aFLQKtzSA9f0dhDqthKHESdfbqxvKzhkBjvTJ5Na EgjKoKfoQTh5xuIv3HLhtDo5PeasPgQl9cPJeriqmqlS+UhY5BGYcMc1AO/TX0fsDaQz96ko at3RUW7sff/qPgVzSurk+DV5h866gPdn5Jdjohyl2F1rzRl6dnaAIyg49zlwZOnPHJGKye+B meqUCnPRglhkpNqXR3v1ulbWpfwhdNDvWT82qTG/qsFy/agjJvxwLuEBeoGc1dPWasO8Nztt 0dqf1Lpeg6SX2yJd76WVS4znt88OEbx/QL2PTJ/YtSepS68WaeKuARKPukkU+QXDep0gaLPl /TvU5xAZndNB3rYnpmoLb32pDHlrJbZUVyTMqc3J2EYM6aaizCpg4VEvVpVSqUT4D9MuREhu PeZ3SvEazQARAQABiQF3BB8BCAAhBQJWzrFTFwyAAWHe5yZt8RJL0vaU1MfDto5dBmeFAgcA AAoJEJVk7a1LmFrdy2QJ/AysDdFIMCRiaqEellprZQyEz5I/qZJEi6yRfXH813hhISFz6moh urZYLQ9SRdyMntT8W3Oc4pJc9fF9RSnY0SSQY/arZbrvsv6hKb1KtIK7P5mLS914J9buxEcJ SWeVuOuMA9aCNqg5uMu19pH5pXayORfbv+K7vFPiyllZ64ShUWZJL69vAc/TsbvMrGtG1M4P qyWCOKEiUT93zhVGQoA0aUYjMAZoyvozZCuieo4O8hkPgMz9lka+3bqQBSOB+qO4Iz+CZs0k Lw7Soga6bRqLK86DH99WjTA6Oj1r8Won+j4V9fnTDCVJoSyqdVHLySDv/lHaNu4Ia4AO4i2d shmLw03gOUvoWLJx5X01A5Zio4FvecnpZqQ0Wz5Ph9MiK3lwarfjonTOLeNGd5BpdnHu5VRC fJml7uAYeyKsD8C4tEBEZXdheW5lIEdlcmFnaHR5IDxkZXdheW5lLmdlcmFnaHR5QGNvbnNj aXVtaW50ZXJuYXRpb25hbC5jb20uYXU+iQGXBBMBCABBAhshCwsKDQkIDAcLAwIECBUKCQgL AwIBBRYDAgEAAh4BAheAFiEEC8bIxjMx+sDl4ZCClWTtrUuYWt0FAl5UUOgACgkQlWTtrUuY Wt3xZAn/W/mq5nDhLIfqxVM9GbU8rGzNsGLfnt5NCVcWlBKhgxOOw9EWkcRTMymwX9OMqwxI +te6Gvy7rG53T2xprtsQyqESZmjWcUSEPsQ9hjw4VZCL15ftBeZMYyO2T1e41UImXAlftleT 2kXCktgyAfwfCzHhFiZM8k9QMFQV1x+JukJ9xPFBgICRLsLsVNVw/R1L7KqARuws4HqXxY1J SCpO+FB4b6tWSIRKbzlb6tctdKppKbG/adVYuoK61ngvmsAzy/9OLhF8u1MNCgyFd2woOErh /zyuap8KvJZMlwAIqpjsoHyXsa0cq8A/uNQSmodwBpRsEGXCmZIZq2FJw6N+38to8C8m97q0 YWrY63VsoA6hA4A4/ywzE3EiwGvqJQBMRv2ET3TIdTyLoEIwXq2bDPU7XTZGh5UZEsKFMHH5 228= Message-ID: <028a9ca5-b935-3de1-5edd-adb959c1116a@heuristicsystems.com.au> Date: Fri, 28 Feb 2020 17:22:59 +1100 User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <93893C00-93BD-4C71-943E-8751DF2854FE@mail.sermon-archive.info> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 48TKK91d4bz4NSm X-Spamd-Bar: -------- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=heuristicsystems.com.au header.s=hsa header.b=Sc7QEQpv; dmarc=none; spf=pass (mx1.freebsd.org: domain of dewayne@heuristicsystems.com.au designates 203.41.22.115 as permitted sender) smtp.mailfrom=dewayne@heuristicsystems.com.au X-Spamd-Result: default: False [-8.47 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; R_DKIM_ALLOW(-0.20)[heuristicsystems.com.au:s=hsa]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; FROM_HAS_DN(0.00)[]; DWL_DNSWL_MED(-2.00)[heuristicsystems.com.au.dwl.dnswl.org : 127.0.4.2]; R_SPF_ALLOW(-0.20)[+mx:c]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-questions@freebsd.org]; TO_DN_NONE(0.00)[]; RCVD_DKIM_ARC_DNSWL_MED(-0.50)[]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; HAS_XAW(0.00)[]; DKIM_TRACE(0.00)[heuristicsystems.com.au:+]; RCVD_IN_DNSWL_MED(-0.20)[115.22.41.203.list.dnswl.org : 127.0.4.2]; DMARC_NA(0.00)[heuristicsystems.com.au]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; IP_SCORE(-3.27)[ip: (-9.72), ipnet: 203.40.0.0/13(-4.22), asn: 1221(-2.42), country: AU(0.01)]; ASN(0.00)[asn:1221, ipnet:203.40.0.0/13, country:AU]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 28 Feb 2020 06:25:19 -0000 On 28/02/2020 11:34 am, Doug Hardie wrote: > I have encountered an inconsistent result in DNS resolution that I am unable to explain. The situation is three servers with completely different IP addresses on three different internet connections. All three are via different companies. In the DNS records for the domain I have an A record for each server with the name A.domain, B.domain, and C.domain. Each points to the appropriate IP address. The name www.domain (and also just domain) have 3 A records: one for each of the 3 servers. The goal is to have a fail over such that A is the primary server, and if it fails, then try B, and finally C. Load balancing is not desirable because the web transactions require numerous exchanges and need to all use the same server. > > On Frontier, Spectrum, and Charter connections, host www.domain lists the 3 servers in the order they are defined in the DNS records. Every time I run host I get the same result. However, there is one PC running windows 10 that connects via the charter supplied modem and is configured for DNS at the modem address that gets the addresses in random order. It appears to be trying to do load balancing. When I use Charter's official DNS servers, I don't see that. But if I use the modem then even FreeBSD 11.1 gets the random results. > > The spectrum interface has the same issue. The official DNS servers are consistent, the modem as a DNS server is random. I thought the TTL for the domain would be honored by the DNS servers. That doesn't always appear to be the case, or the modem DNS servers are rotating their responses from their cache. However, shouldn't the client computers cache the DNS response? Windows does not appear to be doing that. > > -- Doug > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" > Yes, Windows boxes cache the results, to check, open cmd prompt ipconfig /displaydns I'd suggest that the modem isn't caching and rotating dns responses as expected.