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diff --git a/doc/dnssec-guide/getting-started.rst b/doc/dnssec-guide/getting-started.rst new file mode 100644 index 0000000..ff3ae2c --- /dev/null +++ b/doc/dnssec-guide/getting-started.rst @@ -0,0 +1,147 @@ +.. Copyright (C) Internet Systems Consortium, Inc. ("ISC") +.. +.. SPDX-License-Identifier: MPL-2.0 +.. +.. This Source Code Form is subject to the terms of the Mozilla Public +.. License, v. 2.0. If a copy of the MPL was not distributed with this +.. file, you can obtain one at https://mozilla.org/MPL/2.0/. +.. +.. See the COPYRIGHT file distributed with this work for additional +.. information regarding copyright ownership. + +.. _getting_started: + +Getting Started +--------------- + +.. _software_requirements: + +Software Requirements +~~~~~~~~~~~~~~~~~~~~~ + +This guide assumes BIND 9.18.0 or newer, although the more elaborate manual +procedures do work with all versions of BIND later than 9.9. + +We recommend running the latest stable version to get the most +complete DNSSEC configuration, as well as the latest security fixes. + +.. _hardware_requirements: + +Hardware Requirements +~~~~~~~~~~~~~~~~~~~~~ + +.. _recursive_server_hardware: + +Recursive Server Hardware +^^^^^^^^^^^^^^^^^^^^^^^^^ + +Enabling DNSSEC validation on a recursive server makes it a *validating +resolver*. The job of a validating resolver is to fetch additional +information that can be used to computationally verify the answer set. +Contrary to popular belief, the increase in resource consumption is very modest: + +1. *CPU*: a validating resolver executes cryptographic functions on cache-miss + answers, which leads to increased CPU usage. Thanks to standard DNS caching + and contemporary CPUs, the increase in CPU-time consumption in a steady + state is negligible - typically on the order of 5%. For a brief period (a few + minutes) after the resolver starts, the increase might be as much as 20%, but it + quickly decreases as the DNS cache fills in. + +2. *System memory*: DNSSEC leads to larger answer sets and occupies + more memory space. With typical ISP traffic and the state of the Internet as + of mid-2022, memory consumption for the cache increases by roughly 20%. + +3. *Network interfaces*: although DNSSEC does increase the amount of DNS + traffic overall, in practice this increase is often within measurement + error. + +.. _authoritative_server_hardware: + +Authoritative Server Hardware +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +On the authoritative server side, DNSSEC is enabled on a zone-by-zone +basis. When a zone is DNSSEC-enabled, it is also known as "signed." +Below are the expected changes to resource consumption caused by serving +DNSSEC-signed zones: + +1. *CPU*: a DNSSEC-signed zone requires periodic re-signing, which is a + cryptographic function that is CPU-intensive. If your DNS zone is + dynamic or changes frequently, that also adds to higher CPU loads. + +2. *System storage*: A signed zone is definitely larger than an unsigned + zone. How much larger? See + :ref:`your_zone_before_and_after_dnssec` for a comparison + example. The final size depends on the structure of the zone, the signing algorithm, + the number of keys, the choice of NSEC or NSEC3, the ratio of signed delegations, the zone file + format, etc. Usually, the size of a signed zone ranges from a negligible + increase to as much as three times the size of the unsigned zone. + +3. *System memory*: Larger DNS zone files take up not only more storage + space on the file system, but also more space when they are loaded + into system memory. The final memory consumption also depends on all the + variables listed above: in the typical case the increase is around half of + the unsigned zone memory consumption, but it can be as high as three times + for some corner cases. + +4. *Network interfaces*: While your authoritative name servers will + begin sending back larger responses, it is unlikely that you need to + upgrade your network interface card (NIC) on the name server unless + you have some truly outdated hardware. + +One factor to consider, but over which you really have no control, is +the number of users who query your domain name who themselves have DNSSEC +enabled. As of mid-2022, measurements by `APNIC +<https://stats.labs.apnic.net/dnssec>`__ show 41% of Internet users send +DNSSEC-aware queries. This means that more DNS queries for your domain will +take advantage of the additional security features, which will result in +increased system load and possibly network traffic. + +.. _network_requirements: + +Network Requirements +~~~~~~~~~~~~~~~~~~~~ + +From a network perspective, DNS and DNSSEC packets are very similar; +DNSSEC packets are just bigger, which means DNS is more likely to use +TCP. You should test for the following two items to make sure your +network is ready for DNSSEC: + +1. *DNS over TCP*: Verify network connectivity over TCP port 53, which + may mean updating firewall policies or Access Control Lists (ACL) on + routers. See :ref:`dns_uses_tcp` for more details. + +2. *Large UDP packets*: Some network equipment, such as firewalls, may + make assumptions about the size of DNS UDP packets and incorrectly + reject DNS traffic that appears "too big." Verify that the + responses your name server generates are being seen by the rest of the + world: see :ref:`whats_edns0_all_about` for more details. + +.. _operational_requirements: + +Operational Requirements +~~~~~~~~~~~~~~~~~~~~~~~~ + +.. _parent_zone: + +Parent Zone +^^^^^^^^^^^ + +Before starting your DNSSEC deployment, check with your parent zone +administrators to make sure they support DNSSEC. This may or may not be +the same entity as your registrar. As you will see later in +:ref:`working_with_parent_zone`, a crucial step in DNSSEC deployment +is establishing the parent-child trust relationship. If your parent zone +does not yet support DNSSEC, contact that administrator to voice your concerns. + +.. _security_requirements: + +Security Requirements +^^^^^^^^^^^^^^^^^^^^^ + +Some organizations may be subject to stricter security requirements than +others. Check to see if your organization requires stronger +cryptographic keys be generated and stored, and how often keys need to be +rotated. The examples presented in this document are not intended for +high-value zones. We cover some of these security considerations in +:ref:`dnssec_advanced_discussions`. |