When you create a new LLP listener channel in Iguana, you will need to supply a port number. This is a number between 1 and 65535 that identifies the TCP connection that an application such as Iguana uses to send or receive information. For example, port 80 is the standard connection used by your web browser to send and receive information to and from the Internet.

	For more information on TCP ports, which are also called Internet sockets, see the Wikipedia entry on TCP ports.

By default, when you create a new channel, Iguana will select a port that is not currently in use. However, you can specify any port you want.

Note that there is no standard HL7 port: in most health care environments, HL7 messages are transmitted, using the LLP protocol, through a number of different ports. Because there is no standard port, you can choose whatever port you like for your Iguana channel, provided it is not in use.

The following tips may help you manage your ports effectively:

• Be sure not to use a port that is likely to be used by other applications you are running. Even if such a port is not in use now, there are likely to be conflicts in the future. Examples of such ports include 443 (HTTPS), 1433 and 1434 (Microsoft SQL Server) and 3306 (MySQL). For a complete list of ports in common use, see this list of commonly used ports.
• If you are using a large number of channels or using a number of servers, choose a block of consecutive ports that is not in use on any of your servers. This will ensure that you can transfer channels to and from servers without creating any conflicts.
• If you are running a test Iguana server that duplicates the channels in your production environment, ensure that the LLP Listener source components and LLP Client destination components of your test server channels use different ports from those used in your production server. A port can only be used by one server at a time.