08. projects / domains: working with dns

DNS OVERVIEW DNS is the system used to connect domain names to IP addresses. When you make a request for a website the browser performs a DNS query. It's usually the recursive resolver that carries out this work going to the root DNS nameserver TLD nameserver and the authoritative server if it isn't found in the cache.

DNS RECORDS There are a number of different types of DNS records that can be used together to create a DNS configuration. Some of the common information that you might see in a DNS record are:

Host Name: The hostname of www
IP Address or URL: The IP address (or domain or in the case of a CNAME record)
TTL (Time to live): The length of time the recursive server should keep a particular record in its cache.
Record Type: For example CNAME

COMMON DNS RECORD TYPES:

A: Translates domain names into IPv4 addresses.
AAAA: Similar to A but for IPv6 addresses. Not supported on Epycbyte.
ALIAS: Maps a domain name to another domain name. Can only be used at the zone apex.
CAA: Specifies certificate authorities for domains. Epycbyte adds CAA records for Let's Encrypt.
CNAME: Aliases a domain name to another domain name. Cannot be used at the zone apex.
HTTPS: Similar to CNAME but can be used at the zone apex. Includes additional info like ALPN protocols.
DNS Propagation: The process of updating DNS records across servers and caches.

DNS PROPAGATION DNS propagation time varies depending on the DNS provider. Epycbyte typically takes 60 seconds for DNS records to propagate fully.

DNS BEST PRACTICES

Check existing DNS records before switching providers.
Shorten TTL to 60 seconds about 24 hours before making changes.
Use tools like WhatsMyDNS.net to monitor propagation.
Update DNS records once propagation is confirmed.

TROUBLESHOOTING Common issues include:

Misconfigured DNS records
Incorrect TTL settings
Slow propagation due to large TTL
CNAME loops