This is true, `iptables` is not a service. Same goes for `alsa` (and certainly many other packages using this trick). But at the same time this is very handy to be able to temporary stop `iptables` with `sv stop iptables` and restart it with `sv start iptables`. Of course, in that case you will lose all the rules created by other services. Most distros I've used solve this new problem by automatically saving the iptables rules on exit, which I usually disable as it gets in the way of sshguard whose purpose it to temporary block some hosts. But it could make sense for some people.
`sv check` does more than just looking for the presence of a service in `/var/service`. See `man sv`:
```
...
check Check for the service to be in the state that's been requested.
Wait up to 7 seconds for the service to reach the requested
state, then report the status or timeout. If the requested
state of the service is up, and the script ./check exists in the
service directory, sv runs this script to check whether the
service is up and running; it's considered to be up if ./check
exits with 0.
...
```
@Gottox
You are right, using `sv start` does nothing more. I thought it would wait for the program to start but without the `./check` script it does nothing more. Now, the difficulty is to add the `./check` script as this is not trivial.