Issue when using SRV records

I'm not actually sure if there's anything the router can do about this, but I figured I'd see if anyone else has run into this. I have DNS setup like so (domain and IP changed to protect the guilty):


I have mc-router set up like so (deployed to docker swarm, so `tasks.example` resolves to the container):

```
version: "3.8"

services:
...
router:
image: itzg/mc-router
ports:
- target: 25565
published: 25565
mode: host
networks:
- minecraft
- public
command: --mapping=minecraft.example.com.=tasks.example:25565
...
```

In the server list in minecraft, the server shows `Can't connect to server`, but oddly enough the mc-router logs show this:

```
time="2022-04-10T01:45:18Z" level=info msg="Got connection" client="x.x.x.12:52847"
time="2022-04-10T01:45:18Z" level=warning msg="Unable to find registered backend" serverAddress=example.com
time="2022-04-10T01:45:18Z" level=info msg="Got connection" client="x.x.x.12:52848"
time="2022-04-10T01:45:18Z" level=info msg="Connecting to backend" backendHostPort="tasks.example:25565" client="x.x.x.12:52848" server=minecraft.example.com.
time="2022-04-10T01:45:18Z" level=info msg="Finished relay frontend->backend" amount=0 client="x.x.x.12:52848"
time="2022-04-10T01:45:18Z" level=info msg="Finished relay backend->frontend" amount=0 client="x.x.x.12:52848"
```

Because of how Minecraft connects (I guess), even though the server list says `Can't connect to server`, I'm able to connect, because it uses `minecraft.example.com.` as the server name (from the SRV record). It only uses `example.com` when trying to refresh the list (which is unfortunate, because it means you can't point multiple SRV records at the same DNS name which points to mc-router, but at least CNAME records are easy).

I'm wondering if there's anything that I'm doing wrong to cause the server list to show `Can't connect to server`, since mc-router clearly responds affirmatively to the request for `minecraft.example.com.` but not to the request for `example.com`.

Let me know if there's more info I can provide for any of this, I hope this is enough information to communicate the setup clearly.

EDIT: I should mention that adding a second mapping for `example.com=tasks.example:25565` also works, but I was hoping there's something simpler that I'm missing.

Start by reproducing the Docker Swarm SRV setup described in the issue and compare the hostname used for the server-list status request with the hostname used for connection routing, using the reported logs as the baseline. Done means determining whether mc-router should handle both hostnames automatically and documenting or validating the expected behavior without relying on a duplicate mapping.

Written by the indexing model from the issue text.