Permission denied when knocking a domain address (instead of ip address)

[Basti1512]

When connected via mobile network I'm not able to issue a port knock to a domain address (e.g. server.domain.com). I'm getting the error message "Permission denied", but port knocking an IP address is no problem.

Any ideas? Do other have the same problem?

Samsung A5 2016 with Android 7.0 (January patch)

Regards
Basti

[TDFKAOlli]

Hi,
I cannot reproduce the issue on my Huawei P10 lite Android 7. I can knock IP adresses as well as a domain. Maybe your domain is not valid or could not be resolved? Does the app has networking rights on your phone?
Cheers,
TDFKAOlli

[Basti1512]

Sorry for my late answer. It depends on the smartphone. Using my Samsung Galaxy S7 it is working without any problems. At the same time my A5 shows the "Permission denied" message.

[TDFKAOlli]

Maybe a different Android version on both phones?

According to google search we only need:

This is already done, as such we should have access. Have you checked that the app has this permissions on your A5?

Some sites are talking about this permission is also needed:

But I think it is not good to just try and add additional permissions we don't need. We should be fine with just "internet".

Can you fetch a log from that phone?