add dns notes

networking/servers/dns.md

@@ -0,0 +1,44 @@
+---
+title: "dns"
+tags: [ "networking", "host" ]
+---
+
+| Record      |  Type               | Example                                |
+|:-----------:|:--------------------|:---------------------------------------|
+| A Record    | IPv4 Address        | "$domain".com                          |
+| AAAA Record | IPv4 Address        | "$domain".com                          |
+| CNAME       | Alternative Address | "$domain".rs, "$subdomain.$domain".com |
+| NS          | Nameserver          | ns1.fastname.com                       |
+| MX          | Email server        | "$domain".com                          |
+| TXT         | Literally anything,including ownership of a domain |         |
+|             |                     |                                        |
+
+Query a host with the `host` command.
+
+```bash
+host $domain.$tld
+```
+
+
+```bash
+host $domain.$tld 9.9.9.9
+```
+
+> dmz.rs has address 77.105.27.232
+> dmz.rs mail is handled by 10 kralizec.dmz.rs.
+> dmz.rs mail is handled by 20 splint.rs.
+
+This shows the MX record has a secondary handler, called splint.rs.
+
+You can also add a specific nameserver:
+
+Request a specific record type (`CNAME`, `TXT`, et c.):
+
+```bash
+torsocks host -T -t $RECORD_TYPE $domain
+```
+
+## Troubleshooting
+
+The `host` command uses UDP.
+You can change to TCP by using `host -T`.