$ cat $HOME/.digrc
List specific types of RRs (Resource Records)
There are about 40 DNS Resources Records types, but you only have to know 5 of them:
- A : Address record (IPv4); AAAA for IPv6,
- CNAME : Canonical Name. Aliases to A or AAAA records,
- SOA : Start Of Authority: primary name server, email of the domain admin, domain serial number, and timers relating to refreshing the zone,
- MX : Mail eXchange. Points to a mail server,
- NS : Name Server (a DNS).
If you ever get confused about whether or not dig found any result for your query, check the ANSWER field from the header; if it's at 0, your query returned no proper answer.
Batch mode: multiple queries in one go
Batch mode takes a filename as input; the file must be plain text and contain one domain per line:
Make that DNS talk !
A zone transfer is a mechanism allowing an administrator to replicate DNS databases across a set of DNS servers. There are two methods: full (aka AXFR) and incremental (aka IXFR). Zone transfers were often used by people wanting to retrieve a list of all the Resource Records of a DNS server. Nowadays, most servers will refuse your request, mostly for security reasons.