Hey guys. I have a few selfhosted systems that are available to the public. Its getting difficult to notice if any wrong port is still open or some web server is out of date. I am looking for a (foss) tool that can reguarly monitor my systems (via their public ip/domain) and notify me if any port that I not specifically allowed (in a config) is open. Additionally it would be cool if it checked all open ports if they provide out of date software (like webservers) or known security issues.

I found nikto, but it feels like its doing only half of what I want. greenbone feels way to bloated for my use case.

Do you know any kind of software that would do something like that?