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| = DNS: The Domain Name System =
| | The 44Net DNS service provides name resolution and delegation for 44Net users. Most participants use it to publish hostnames for their systems, starting with a callsign-based subdomain and adding records as needed. |
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| The Domain Name System is the mechanism by which symbolic host names, such as ''kz2x.ampr.org'' are translated into numeric host IP addresses, such as 44.44.48.2. It is heavily used on AMPRNet. Cleverly
| | == Getting Started == |
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| DNS is an Internet standard that is defined by a set of "Request for Comment" documents, or RFCs. The current revision of the DNS specification is in [https://datatracker.ietf.org/doc/html/rfc1035 RFC1035]. | | A typical DNS path on 44Net: |
| | # Claim a callsign-based subdomain under ampr.org. |
| | # Create DNS records that map hostnames to IP addresses. |
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| == Historical Background ==
| | This is sufficient for publishing things like web servers, gateways, remote stations, and repeaters. |
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| Before DNS, individual sites on the Internet maintained a local mapping of host names to IP addresses in the form of a "hosts" file; this was often a text file resident on each Internet-connected computer. However, as the network grew, this quickly became untenable: not only did the file itself become so large as to be unwieldy and slow to search, keeping it up to date required significant effort. Furthermore, coordinating updates from many different organizations, and avoiding name collisions as new hosts were added, added even more complexity.
| | * [[DNS/Portal/Subdomains|Claiming a Subdomain]] |
| | * [[DNS/Portal/Records|Managing Records]] |
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| A clever insight was that the problem could be addressed using the network itself, by providing a network service that could translate between host names and IP addresses. Early work around this idea ultimately lead to DNS.
| | == Running Your Own DNS == |
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| == Concepts ==
| | Some participants run their own DNS servers rather than relying only on the Portal. |
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| The DNS on the client/server model, in which ''client'' machines send name service queries to DNS ''servers'' scattered around the Internet, which in turn, provide answers. The process of answering a query related to a host name is called "resolution." Resolved queries may be "cached" by servers for some period of time, called the "time to live" or TTL, given by the source server.
| | In this approach, control of a domain is delegated to local systems, while remaining part of the ampr.org domain. |
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| === Domains, Zones, and Authority ===
| | This supports automation, custom workflows, and closer integration with locally managed services. |
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| Names are hierarchical, and organized into ''domains'': Starting from ".", the "root", and descending through a "top-level" domain (TLD) such ".org", then through an organizational domain such as "ampr". Each such level forms a "domain", so that ".org" and "ampr.org" are separate domains. This organization provides resilience against collisions, since names need only be unique within a domain, and and facilitating separation of administrative concerns.
| | * [[DNS/Portal/Delegations|Delegating DNS to an Independent Name Server]] |
| | * [[DNS/Setup/OpenBSD_Resolver|Setting up a Recursive Resolver on OpenBSD]] |
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| Collections of domains that fall under a single administrative entity form "zones". A zone is said to be authoritative for the domains under its control, but not otherwise; non-authoritative data typically comes out of caches established in response to earlier queries. Authoritative responses to queries always override cached data.
| | == Understanding DNS == |
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| === Servers, Resolvers, and Stub Resolvers ===
| | For background on how DNS works (with 44Net use in mind): |
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| As mentioned, clients resolve queries about domain names by sending those queries to servers, but different kinds of servers play different roles:
| | * [[DNS/Overview|DNS Overview and Concepts]] |
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| * Servers, or Authoritative Servers, are the ultimate sources of authority for domains under some zone. They accept queries answer them, either with resolved data or with an error, such as when a query is issued for name that does not exist. | |
| * Resolvers, or Recursive Servers, are intermediaries; they accept "recursive" queries and forward these to other servers until they receive a definitive reply. They then usually cache the results so that subsequent requests for the same query can be answered quickly. The cached data expires once its TTL is exceeded.
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| * Stub resolvers are small bits of software embedded in client programs that make DNS queries: these program fragments send queries to remote servers and interpret the results, providing them the rest of the program.
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| Usually, any program that wants to make use of the DNS will do so via a stub resolver, which will forward the query to some recursive server. The stub resolver learns about what recursive server to send its queries to via some administrative mechanism; for example, a DHCP server might supply the IP address of the server to use.
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The 44Net DNS service provides name resolution and delegation for 44Net users. Most participants use it to publish hostnames for their systems, starting with a callsign-based subdomain and adding records as needed.
Getting Started
A typical DNS path on 44Net:
- Claim a callsign-based subdomain under ampr.org.
- Create DNS records that map hostnames to IP addresses.
This is sufficient for publishing things like web servers, gateways, remote stations, and repeaters.
Running Your Own DNS
Some participants run their own DNS servers rather than relying only on the Portal.
In this approach, control of a domain is delegated to local systems, while remaining part of the ampr.org domain.
This supports automation, custom workflows, and closer integration with locally managed services.
Understanding DNS
For background on how DNS works (with 44Net use in mind):
