Firewalls work by blocking all
ports except those explicitly needed by applications installed on the computer.
Most software firewalls need no user intervention, but occasionally you may need
to open a port for an new application manually.
|
The port numbers are divided into three
ranges: the Well Known Ports, the Registered Ports, and the Dynamic
and/or Private Ports. |
|
|
|
|
|
|
The Well Known Ports are those from 0 through 1023. |
|
The Registered Ports are those from 1024 through 49151 |
|
The Dynamic and/or Private Ports are those from 49152 through 65535 |
|
|
|
|
|
|
Port Number |
Name |
Description |
Security Concerns |
|
1 |
TCPMUX |
TCP Port Service Multiplexer |
|
|
5 |
RJE |
Remote Job Entry |
|
|
7 |
PING/TRACERT |
ICMP ECHO -
Packet Internet Groper & Trace Route |
Block from Internet |
|
13 |
Daytime |
Network Time Sync with Atomic Clock |
|
|
18 |
MSP |
Message Send Protocol |
|
|
20 |
FTP-Data |
File Transfer Protocol |
Secure |
|
21 |
FTP-Control |
File Transfer Protocol |
Secure |
|
22 |
SSH |
Secure Shell Remote Login Protocol |
|
|
23 |
Telnet |
Telnet |
Secure |
|
25 |
SMTP |
Simple Mail Transfer Protocol |
Block Relay |
|
29 |
MSG ICP |
|
|
|
37 |
TIME |
Time |
|
|
42 |
Nameserv |
Host Name Server |
|
|
43 |
Whois |
WhoIs |
|
|
49 |
Login |
Login Host Protocol |
|
|
53 |
DNS |
Domain Name System |
Secure |
|
67 |
BootP-Server |
Outgoing DHCP |
|
|
68 |
BootP-Client |
Incoming DHCP |
|
|
69 |
TFTP |
TFTP - Trivial File Transfer Protocol |
|
|
70 |
Gopher |
Gopher |
|
|
79 |
Finger |
Finger |
|
|
80 |
HTTP |
HTTP |
|
|
88 |
Kerberos |
Secure Encrypted Login |
|
|
103 |
X.400 |
X.400 |
|
|
108 |
SNA |
SNA Gateway Access Server |
|
|
109 |
POP2 |
Post Office Protocol |
|
|
110 |
POP3 |
Post Office Protocol |
|
|
115 |
SFTP |
Simple File Transfer Protocol |
|
|
118 |
SQL |
SQL Services |
|
|
119 |
NNTP |
Network News Transfer Protocol |
|
|
135 |
NetBIOS |
DCE Endpoint Mapper |
Block |
|
137 |
NetBIOS |
NetBIOS Name Service |
Block |
|
138 |
NetBIOS |
NetBIOS Datagram Service |
Block |
|
139 |
NetBIOS |
NetBIOS Session Service |
Block |
|
143 |
IMAP |
Internet Message Access Protocol |
|
|
150 |
NetBIOS |
NetBIOS Session Service |
|
|
156 |
SQL |
SQL Server |
|
|
161 |
SNMP |
Simple Network Management Protocol |
|
|
179 |
BGP |
BGP - Border Gateway Protocol |
|
|
190 |
GACP |
Gateway Access Control Protocol |
|
|
194 |
IRC |
IRC - Internet Relay Chat |
|
|
197 |
DLS |
Directory Location Service |
|
|
213 |
IPX |
Novell Netware |
|
|
389 |
LDAP |
Lightweight Directory Access Protocol |
|
|
396 |
|
Novell Netware over IP |
|
|
443 |
HTTPS |
HTTP over TLS/SSL |
Enable only if required - otherwise BLOCK |
|
444 |
SNPP |
Simple Network Paging Protocol |
|
|
445 |
|
Microsoft-DS |
Block |
|
458 |
|
Apple Quick Time |
|
|
546 |
DHCPv6 |
DHCP version 6 Client |
|
|
547 |
DHCPv6 |
DHCP version 6 Server |
|
|
563 |
NTTPS |
Network News Transfer Protocol over TLS/SSL |
|
|
569 |
|
MSN |
|
|
636 |
LDAPS |
LDAP over TLS/SSL |
|
|
989 |
FTPS-DATA |
FTP Data over TLS/SSL |
|
|
990 |
FTPS |
FTP Control over TLS/SSL |
|
|
992 |
TenetS |
Telnet over TLS/SSL |
|
|
993 |
IMAP4S |
IMAP over SSL |
|
|
994 |
IRCS |
IRC over TLS/SSL |
|
|
995 |
POP3S |
Post Office Protocol 3 over TLS/SSL |
|
|
|
|
|
|
|
Registered Ports |
|
|
|
|
1080 |
|
Socks |
|
|
1512 |
WINS |
Windows Internet Naming Service |
|
|
1723 |
PPTP |
Point to Point Tunneling Protocol |
|
|
|
|
|
|
|
|
