This is a list of commonly used ports, best thing to do is close all except these and if you find you need them, open others later.
7 Echo systat
11 Active users qotd
17 Quote of the day msp
18 Message Send Protocol ftp-data
20 File Transfer (Data Channel) ftp
21 File Transfer (Control) telnet
23 Telnet smtp
25 Simple Mail Transfer Protocol
42 TCP Nameserver bootps
67 Bootstrap Protocol Server bootpc
68 Bootstrap Protocol Client tftp
69 Trival File Transfer gopher
70 Gopher finger
79 Finger www
80 World Wide Web Kerberos
88 Kerberos pop3
110 TCP post office nntp
119 USENET nfs
2049 Network File System
7 Echo systat
11 Active users qotd
17 Quote of the day msp
18 Message Send Protocol ftp-data
20 File Transfer (Data Channel) ftp
21 File Transfer (Control) telnet
23 Telnet smtp
25 Simple Mail Transfer Protocol
42 TCP Nameserver bootps
67 Bootstrap Protocol Server bootpc
68 Bootstrap Protocol Client tftp
69 Trival File Transfer gopher
70 Gopher finger
79 Finger www
80 World Wide Web Kerberos
88 Kerberos pop3
110 TCP post office nntp
119 USENET nfs
2049 Network File System