List of all important Port Numbers

1. Port 21 FTP port (used for all ftp based file transfer)
2. Port 22 SSH Server listening port
3. Port 23 Telnet port
4. Port 25 Smtp mail port
5. Port 42 WINS Replication port
6. Port 43 WHOIS port
7. Port 53 DNS port
8. Port 67 DHCP port
9. Port 79 ETRN Finger port-Finger command for SMTP mailservers
10. Port 80 HTTP port
11. Port 102 X.400 port
12. Port 110 POP3 port
13. Port 115 SFTP port- Secure File Transfer port
14. Port 119 Newsgroup port
15. Port 123 Network Time Protocol port
16. Port 135 RPC Locator service port (Remote Procedure Call)
17. Port 137 NetBIOS Name service port/WINS
18. Port 143 Internet Message Acess Protocol 4 port (IMAP4)
19. Port 161 Simple Network Management Protocol port (SNMP)
20. Port 179 Border Gateway Protocol port
21. Port 379 Site Replication Service port (SRS)
22. Port 389 Light Weight Directory Access Protocol port (LDAP)
23. Port 443 Secure HTTP traffic port (SSL port)
24. Port 445 Microsoft Active Directory & SMB Protocol port
25. Port 465 Google Mail Outgoing Mail Server
26. Port 636 LDAP over SSL
27. Port 993 Secure Internet Message Access Protocol port (Secure IMAP port)
28. Port 995 Google Mail Incoming POP3 Mail server (Gmail port)
29. Port 1026 Calendar Access Protocol port (CAP)
30. Port 1080 SOCKS/Online Chatting/Hotmail
31. Port 1090 Real Audio port
32. Port 1433 SQL Server & SQL server replication port
33. Port 1434 SQL sever Monitoring port
34. Port 1521 Default Oracle port
35. Port 1677 Novell Groupwise
36. Port 1071 Layer Two Tunnelling port
37. Port 1720 H.323 port
38. Port 1723 Point To Point Tunnelling Protocol port(PPTP port)
39. Port 1900 Media Center Extender - Xbox 360 port
40. Port 2409 SPAM Fighter Content Classification port
41. Port 3101 Balckberry Enterprise Server Syncronization port (BES)
42. Port 3306 Default MySQL port
43. Port 3389 Remote Desktop port and Terminal Services port
44. Port 3390 Media Center Extender -Xbox 360 port
45. Port 3535 GoDaddy Secure SMTP Relay port
46. Port 4321 RWHOIS port
47. Port 4664 Google Desktop Search port
48. Port 5190 AOL Instant Messenger port
49. Port 5500 DualDesk port
50. Port 5631 PCAnywhere 5631 TCP incoming port
51. Port 5632 PCAnywhere 5632 UDP incoming port
52. Port 5900 RealVNC Default Remote Control port
53. Port 7070 Real Streaming Audio port
54. Port 7100 Novell Groupwise
55. Port 8000 Mirra Personal Server Communications port
56. Port 8080 HTTP Internet traffic port
57. Port 8799 GPRS Internet Access Proxy port
58. Port 8880 CDDB port
59. Port 9100 Google Web Acceletrator port
60. Port 19430 Mirra Personal Server Directory port
61. Port 39720 LimeWire Communication port

Source : Internet