From ddbc51ada2b666fa2a08b0bb9127a1730dc99fa9 Mon Sep 17 00:00:00 2001 From: Dennis Baaten Date: Thu, 27 Jun 2019 16:50:36 +0200 Subject: [PATCH] Create DNS-records-overview.md --- DNS-records-overview.md | 48 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 DNS-records-overview.md diff --git a/DNS-records-overview.md b/DNS-records-overview.md new file mode 100644 index 0000000..d3aceff --- /dev/null +++ b/DNS-records-overview.md @@ -0,0 +1,48 @@ +# Under constrution!! +This document lists the basic usage of commonly used DNS records. It can be used to track commonly made mistakes. + +# A +* Points to an IPv4 address. +* Does not point to anyhting else. +* Record does not start (left side) with _ or -. + +# AAAA +* Points to an IPv6 address. +* Does not point to anyhting else. +* Record does not start (left side) with _ or -. + +# MX +* Points to an A and/or AAAA record. +* Preferrably does not point to other record types, but the use of CNAME records is seen in practice. RFC's are inconsistent on this. +* Has a priority value. + +# CNAME +* Points to other records (A, AAAA, CNAME). +* Be carefull with CNAME chaining; don't use too many CNAMEs in a row. +* The end of a CNAME chain is always an A an/or AAAA record. +* **Can only be combined with NS / SOA records if left side is equal.** + +# SRV +* Records starts (left side) with _. +* Points to an A and/or AAAA record. +* Has a priority value. + +# NS +* Points to an A and/or AAAA record. +* **Used to point to subzones.** +* **Used to indicate what is inside the parent zone.** +* **Each zone needs this to indicate what is inside the parent zone as a reference to this zone.** + +# SOA +* Mandatory for every DNS zone. +* Contains the following information (seperated by a single white space): + * FQDN of the primairy name server followed by a trailing dot. + * e-mail address of the DNS administrator (followed by a trailing dot, the @ replaced with a dot). + * an opening round bracket "(". + * serial number that is changed (increased) on every zone change. + * refresh time (in seconds) for a secondary name server to check the primairy name server for changes in the zone. + * retry time (in seconds) for a secondary name server for requesting the serial number when the primary name server did not respond on the previous request. + * expire time (in seconds) after which a secondary name server should stop answering requests if the primary name server is not responding. + * Negative caching time to live (in seconds) which is the time a caching name server should cache a negative result (indicating that a name does not exist) coming from the authorative name server before trying again. + * a closing round bracket ")". +