Also, I moved the "versio" endpoint: `version.sslip.io` →
`version.status.sslip.io`. It seemed to make more sense to corral the
special endpoints under `status`.
- The metrics aren't fleshed out. In fact, there's only two so far:
1. uptime
2. number of queries
- Even though the metrics aren't complete, I'm checking it in because
this commit is already much too big.
- I moved the version information to `version.status.sslip.io`;
previously it was at `version.sslip.io`. I didn't want one endpoint
for both metrics & version (worry: DNS amplification), and I wanted a
consistent subdomain to find that information (i.e.
`status.sslip.io`).
- I'm not worried about atomic updates to the metrics; if a metric is
off by one, if I skip a count because two lookups are happening at the
exact same time, I don't care.
- The `Metrics` struct is a pointer within `Xip` because I might have
several copies of `Xip` (if I'm binding to several interfaces
individually), but I must only have one copy of `Metrics`
- I only include the metrics I'm interested in, usually because it took
some work to implement that feature. I don't care about MX records,
but I care about IPv6 lookups, DNS-01 challenges, public IP lookups.
- got rid of a section of unreachable code at the end of
`ProcessQuestion()`; I was tired of Goland flagging it. I had it there
mostly because I was paranoid of falling through a `switch` statement
I didn't want a really long domain for the key-value store; I wanted a
short, easy-to-remember domain. And it cost $400 for ten years.
Many good domains (e.g. keyvalue.store, kv.io)
were taken, and some weren't easily registered (e.g. the Albanian
domain, keyv.al).
Browsing these domains that were never put into use is like strolling
along the Boulevard of Broken Dreams: high hopes dashed against the hard
rocks of reality.
We enable special behavior under the `kv.sslip.io` subdomain: it can be
treated as a key-value store, the sub-subdomain being the key, and the
TXT record being the value.
For example, to write ("put") the value "12.0.1" to the key
"macos-version" on the `ns-gce.sslip.io.` nameserver, you'd use the
following `dig` command:
```shell
dig @ns-gce.sslip.io. txt put.12.0.1.macos-version.kv.sslip.io.
```
To read ("get") the value back, you'd write the following `dig` command:
```shell
dig @ns-gce.sslip.io. txt get.macos-version.kv.sslip.io.
```
Since "get" is the default behavior, you don't need to include it in the
domain name:
```shell
dig @ns-gce.sslip.io. txt macos-version.kv.sslip.io.
```
Finally, when you're done with the key-value, you can "delete" it:
```shell
dig @ns-gce.sslip.io. txt delete.macos-version.kv.sslip.io.
```
Notes:
- Keys are case-insensitive (to accommodate DNS convention). In other
words, `KEY.kv.sslip.io` and `key.kv.sslip.io` return the same TXT
record.
- Values are case-sensitive. `put.CamelCase.style.kv.sslip.io` sets the
TXT record to "CamelCase".
- `put` requests will return the TXT record being put; i.e.
`put.hello.world.kv.sslip.io` returns one TXT record of one string,
`hello`.
- `delete` requests will return the TXT record being deleted; i.e.
`delete.world.kv.sslip.io` returns one TXT record of one string,
`hello`. If the TXT record does not exist, no TXT records will be
returned.
- Values are limited to 63 bytes to mitigate using the sslip.io servers
in a [DNS amplification
attack](https://us-cert.cisa.gov/ncas/alerts/TA13-088A).
- Values are not persistent: if the server is restarted, all values
disappear. Poof.
- Values are not consistent. If a value is set in `ns-aws.sslip.io`, it
does not propagate to `ns-gce.sslip.io` nor `ns-azure.sslip.io`.
Our documentation was wrong; our homepage said to get the origin IP
address by querying the TXT record of the root, i.e. `dig
@ns-aws.nono.io txt . +short`; however, our code worked differently: it
returned the origin IP when the `.ip` TLD was queried.
The new behavior is that it returns the origin IP when `ip.sslip.io.` is
queried, and the documentation now reflects that behavior.
Also, that behavior is marked "experimental" to give us leeway to
change.
[fixes#11]
- Returns version information for DNS server
- Contains 3 strings:
- Semantic version, e.g. "2.2.1"
- Date of compilation
- Latest git hash
Note: the BOSH Release will have a different compilation date &
different git hash than the released executables; the semantic version
will be the same.
- Use HTTP-01 challenge for run-of-the-mill certificates
- White label domains can acquire their own wildcard certificates
- VMware employees have access to *.sslip.io wildcard
- Use DNS-01 challenge for *.w-x-y-z.sslip.io wildcards
`DEVELOPER.md` had the wrong tests (mostly missing newlines); that's
been fixed. Also, I added a new test for DNS records which contain
`_acme-challenge.`, which may enable users to generate wildcard certs
for their sslip.io domains.
When we released our new Golang-based DNS server, we had a banner that
said to let us know if anything breaks, but we neglected to tell them
_how_ to let us know. Now we include a link that opens a GitHub issue.
We describe how to run our pre-built executable within a docker
container. They can figure out the rest from there.
If they don't understand those instructions, they shouldn't be running
their own DNS server.
