X.400. Port is used by default by Microsoft Exchange Server Message Transfer Agents to communicate with one another on internal networks with multiple Exchange servers.
CAP (Novell and Microsoft) Port is used by Novell GroupWise for its Calendar Access Protocol. On some Windows 2000 servers, port 1026 is used by the Windows Task Scheduler or other Windows services.
SOCKS/Online Chat/Hotmail: Port used primarily by instant messaging applications, as well as Hotmail.
NTP: Network Time Protocol port. Used for checking and synchronising time with another computer (time server). Windows Vista uses this port when you configure the clock to automatically synchronize itself with a time server on the Internet. Also used when you configure a Windows Server to sync its time over the Internet.
RPC (Remote Procedure Call) Locator Service Port: Maintains a list of networked services that support RPC and DCOM standards. This list holds information regarding which ports and IP addresses the services are running or listening on.
NetBIOS Name Service port (WINS): Port used by the NetBIOS protocol to find other computers on a workgroup network. On a P2P network this will be done via broadcast.
SQL Server Port & SQL Server Replication Port: Used by SQL Server 6 and above for SQL replication between SQL servers.
SQL Server Monitoring Port: Used by Microsoft SQL Server to monitor SQL server performance.
SNMP port (Simple Network Management Protocol) UDP port used ot manage, configure and gather information about network devices (e.g. firewalls, routers) in a unified manner across manufacturers
Novell GroupWise: Standard port used by Novell GroupWise for TCP/IP communications between clients and agents and the GroupWise Post Office Agent (POA)
L2TP: Layer 2 Tunneling Protocol: Tunneling and encryption standard used to connect two private business networks together over an Internet connection to create a VPN. This protocol is seen as the replacement for PPTP (Port 1723)
PPTP Port: Point to Point Tunneling Protocol: PPTP is a tunneling and encryption standard used to link two private business networks together over an Internet connection to create a VPN. Default protocol for establishing a VPN on Windows 2000 Server .
BGP. Border Gateway Protocol is a routing protocol used to exchange routing information between routers in autonomous networks.
Media Center Extender: XBox 360 port: UDP inbound. Used by Microsoft's XBox 360 when linking to Media Center.
SPAMFighter Content Classification Port: UDP inbound and outbound. Used by SPAMFighter software to communicate with its servers in order to determine which e-mails are spam.
BES Synchronization Port: If you have an outbound firewall, you will need to open this TCP port to enable the BES to sync with the BlackBerry devices. Depending on the configuration, you may also need to port forward port 3101 from the router to the BES.
Remote Desktop Port and Terminal Services Port: TCP inbound & outbound. Used by Windows XP Remote Desktop Connection and Microsoft Terminal Server for remote Desktop Connectoins and/or Terminal Services sessions. For added security it is recommended to change the Remote Desktop port from its default to a value of your choosing.
Media Center Extender - XBox 360 port: TCP Inbound. Port used by XBox 360 to link to Media Center.
SRS Port (Site Replication Services) TCP port used by Microsoft SRS. Allows LDAP enabled servers to replicate between one another information stored on AD domain controllers and Exchange servers.
LDAP Port: TCP port used to find and manage network resources on a hierarchical network system such as Novell Network Directory Trees, and AD Service Domains.
WINS Replication Port (used to replicate NETBIOS name tables from one Windows server to another)
WHOIS port (used for WhoIs requests (for the retrieval of domain name information) to whois servers
S-HTTP (SSL Port) Default port used for SSL encrypted communications. Used for both incoming and outgoing SSL connections.
Microsoft AD and Service Message Block (SMB) protocols. SMB is known as the Microsoft Windows Network, and is the main protocol used by Microsoft Server Operating Systems for client/server acces, and file and printer sharing.
Google Mail Outgoing Mail Server: Non-standard port used by Google for its Outgoing Mail Server for Google Mail. Use this port, smtp.gmail.com and SSL connection (SMTP Server Authentication) when configuring you e-mail client for G-Mail.
DNS port for DNS requests and replies. (used to replicate NETBIOS name tables from one Windows server to another)
PCAnywhere: Port on which a Symantec PC Anywhere host accepts incoming PC Anywhere connections and then continues to communicate with the remote PC.
PC Anywhere UDP incoming port; Port used by Symantec's PC Anywhere for the streaming of screen updates during a PC Anywhere session.
LDAP over SSL: TCP Port used for LDAP over SSL connections. Standard added to LDAP to prevent interception of information and credentials using the LDAP protoocl.
DHCP port for DHCP requests and replies. (Dynamic Host Configuration Protocol) Used by the DHCP server and clients when the client checks with the DHCP server for a new leas and the allocation of an IP addres.
Finger command for SMTP Mailservers ETRN Finger port. This port is used by SMTP mail servers to send ETRN Finger commands to message queue servers so that htose message queue servers are online and ready to accept queued mail. Basically, the port the e-mail server uses to send an ETRN command to your web-hosting company's mail server so that they will delivery any waiting incoming mail.
HTTP Internet Traffic port: The other port through which HTTP Internet traffic also goes through.
CDDB Port: Used by CD mastering software to communicate with an Internet based CDDB server for requests about artist and track names.
GMail Incoming POP3 Mail Server: Non-standard port used by Google for its POP3 Incoming Mail Server for GMail.
TCP 20 and 21
FTP. File Transfer Protocol. 20 and 21 are used for all FTP based file transfers, e.g. with programs like FTP Voyager, WS_FTP, Cute FTP, FTP NOW etc.)
SMTP mail port. Standard port used for SMTP mail delivery. The outgoing mail port used by programs like Outlook Express, Outlook, FoxMail, etc. Also the SMTP outgoing port for mail servers like Axigen Mail Server, CMailServer, Novell GroupWise, Microsoft Exchange, etc.
POP3 Standard port used for POP3 mail delivery and collection. Often referred to as the Incoming Mail port in e-mail programs including Outlook Express, Outlook, Fox Mail, etc.