From 51de98f6a193e8e7e94cdf3723be8beb7c7d8379 Mon Sep 17 00:00:00 2001 From: Talon Date: Mon, 7 Mar 2022 20:49:07 -0700 Subject: [PATCH] docs --- README.md | 21 ++++++++++++++++----- Settings.env | 2 +- 2 files changed, 17 insertions(+), 6 deletions(-) diff --git a/README.md b/README.md index ba77d01..f810eed 100644 --- a/README.md +++ b/README.md @@ -2,27 +2,32 @@ Dynamic DNS for gandi.net +## How it works + * `curl` external IP from [icanhazip.com](https://icanhazip.com) * `curl` to update the configured domain and record on [Gandi via the API](https://doc.livedns.gandi.net/) -* unless the IP has not changed (compared to previous check at +* Unless the IP has not changed (compared to previous check at /tmp/DynGanDiNS.ip) +* Bash without the isms. Portability aimed. * systemd timer included! ## How to use Acquire an API key from Gandi by visiting your account page and finding the -authorized apps UI to generate one. - -Clone this repo locally. Before `make install` update `Settings.env`. After installation the environment variables are sourced from `/etc/sysconfig/DynGanDiNS`. +authorized apps UI to generate one. Then clone this repo locally. Update `Settings.env` with your API key, domain and record name and then run `make install` (sudo as needed). After installation the environment variables are sourced from `/etc/sysconfig/DynGanDiNS` which will look like this (but hopefully with your info by now not empty variables): ```sh -GDDNS_API_KEY= # required API key from Gandi +GDDNS_API_KEY= # API key from Gandi GDDNS_DOMAIN= # the domain name to update. example.com GDDNS_RECORD_NAME= # the record to update. ex. raspi # GDDNS_TTL="3600" ``` > If not using the systemd timer/service then you'll have to supply the environment variables some other way. Also probably don't bother with `make install` just use `DynGanDiNS.sh` how you please. +### Script + +After `make install` the shell script is available in your path (from /bin) as `DynGanDiNS` and you can run that to make sure the environment is properly configured before enabling the timer and walking away. + ### Timer By default the timer is configured to run the service every hour. Use `systemctl edit DynGanDiNS.timer` to override `OnCalendar` as desired. @@ -33,6 +38,12 @@ systemctl enable --now DynGanDiNS.timer ``` > If you already ran the install then the settings are here: /etc/sysconfig/DynGanDiNS +## Why? + +Internet service providers (ISPs) may or may not provide a static IP address for your connection to the World Wide Web. When they do not then it is _dynamic_ which poses a problem for domain name resolution (DNS) trying to associate the name with an IP that might change. To work around this some way of getting the current IP address and telling the DNS about it is required—ideally exactly and only when the IP changes. + +This problem is very common for home computers wanting to expose services behind DNS to the larger network. For example a [Raspberry Pi](https://www.raspberrypi.org/) hosting an artisinal handcrafted website about knitting and gardening. Or maybe a [Wireguard VPN exposing an instance of Pi-hole for ad-block on the go!](https://docs.pi-hole.net/guides/vpn/wireguard/overview/). Or any other reason a server could be useful and you'd rather own instead of rent it. + ## See Also * [Gandi LiveDNS API](https://doc.livedns.gandi.net/) diff --git a/Settings.env b/Settings.env index 68f59f0..fc92f6f 100644 --- a/Settings.env +++ b/Settings.env @@ -1,4 +1,4 @@ -GDDNS_API_KEY= # required API key from Gandi +GDDNS_API_KEY= # API key from Gandi GDDNS_DOMAIN= # the domain name to update. ex. example.com GDDNS_RECORD_NAME= # the record to update. ex. raspi # GDDNS_TTL="3600"