# Setting custom DNS records ## Goal This documentation has the goal of showing how a user can set custom DNS records with `headscale`s magic dns. An example use case is to serve apps on the same host via a reverse proxy like NGINX, in this case a Prometheus monitoring stack. This allows to nicely access the service with "http://grafana.myvpn.example.com" instead of the hostname and portnum combination "http://hostname-in-magic-dns.myvpn.example.com:3000". ## Setup ### 1. Change the configuration 1. Change the `config.yaml` to contain the desired records like so: ```yaml dns_config: ... extra_records: - name: "prometheus.myvpn.example.com" type: "A" value: "100.64.0.3" - name: "grafana.myvpn.example.com" type: "A" value: "100.64.0.3" ... ``` 2. Restart your headscale instance. Beware of the limitations listed later on! ### 2. Verify that the records are set You can use a DNS querying tool of your choice on one of your hosts to verify that your newly set records are actually available in MagicDNS, here we used [`dig`](https://man.archlinux.org/man/dig.1.en): ``` $ dig grafana.myvpn.example.com ; <<>> DiG 9.18.10 <<>> grafana.myvpn.example.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 44054 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 65494 ;; QUESTION SECTION: ;grafana.myvpn.example.com. IN A ;; ANSWER SECTION: grafana.myvpn.example.com. 593 IN A 100.64.0.3 ;; Query time: 0 msec ;; SERVER: 127.0.0.53#53(127.0.0.53) (UDP) ;; WHEN: Sat Dec 31 11:46:55 CET 2022 ;; MSG SIZE rcvd: 66 ``` ### 3. Optional: Setup the reverse proxy The motivating example here was to be able to access internal monitoring services on the same host without specifying a port: ``` server { listen 80; listen [::]:80; server_name grafana.myvpn.example.com; location / { proxy_pass http://localhost:3000; proxy_set_header Host $http_host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header X-Forwarded-Proto $scheme; } } ``` ## Limitations [Not all types of records are supported](https://github.com/tailscale/tailscale/blob/6edf357b96b28ee1be659a70232c0135b2ffedfd/ipn/ipnlocal/local.go#L2989-L3007), especially no CNAME records.