Which ports should I open?

[Geoinline]

Currently I have these ports open in my router (I've disabled ISPConfig firewall Management>Services>Firewall)

FTP 21
SSH 25
DNS 53
www 80
ISPconfig 81
POP3 110
SSL(www) 443
Webmin 10000

When I do a port scan (Tools>Portscanner) I get this:

Port 21 (tcp) is open (ftp)!
Port 22 (tcp) is open (ssh)!
Port 25 (tcp) is open (smtp)!
Port 53 (tcp) is open (domain)!
Port 80 (tcp) is open (www)!
Port 81 (tcp) is open (unknown)!
Port 110 (tcp) is open (pop3)!
Port 143 (tcp) is open (imap2)!
Port 443 (tcp) is open (https)!
Port 953 (tcp) is open (unknown)!
Port 993 (tcp) is open (imaps)!
Port 995 (tcp) is open (pop3s)!
Port 3306 (tcp) is open (mysql)!
Port 48431 (tcp) is open (unknown)!

Which ports should be open?