Scan your web server for open ports that are currently listening
nmap -p 1-65535 localhost
Running nmap for the first time to scan your listening ports may take a few moments.
After scanning all the open ports on your linux web server, nmap will return output similar to following.
Starting nmap V. 3.00 ( www.insecure.org/nmap/ )
Interesting ports on localhost.localdomain (127.0.0.1):
(The 65528 ports scanned but not shown below are in state: closed)
Port State Service
22/tcp open ssh
25/tcp open smtp
80/tcp open http
113/tcp open auth
443/tcp open https
631/tcp open ipp
3306/tcp open mysql
Nmap run completed -- 1 IP address (1 host up) scanned in 111 seconds
It's imperative that you scan your computer regularly to look for vulnerabilities.