IBM SC41-5420-04 manual Configuring TCP/IP Port Restrictions, Paolo

the specified port. If no match is found, the requesting program is not allowed to use the specified port. If any port in the 1-1023 range is restricted, the following message is posted:

Port restriction added but may affect TCP/IP processing

If no user profiles are associated with a specific port, there are no restrictions.

It is not necessary to configure port restrictions unless you are writing your own TCP/IP applications and you want to reserve the use of the applications to certain user profiles.

Note: For an installation in which user-written programs use ports other than the well-known ports, you can consider restricting the use of the well-known ports to the user profiles running the server application. As an example, for File Transfer Protocol (FTP), this would be user profile QTCP.

Configuring TCP/IP Port Restrictions

To configure TCP/IP port restrictions, type option 4 on the Configure TCP/IP menu. The Work with TCP/IP Port Restrictions display is shown (Figure 55).

		Work with TCP/IP Port Restrictions
				System: SYSNAM03
Type options, press Enter.
1=Add	4=Remove
	--Port Range---			User
Opt	Lower	Upper	Protocol	Profile
_	_____	*ONLY	____	__________
	1050	1059	*TCP	PAOLO

Bottom

F3=Exit F5=Refresh F6=Print list F12=Cancel F17=Top F18=Bottom

Figure 55. Work with TCP/IP Port Restrictions Display

Type option 1 (Add) at the input-capable top list entry to get to the Add TCP/IP Port Entry (ADDTCPPORT) display shown in Figure 56 on page 64. You can go directly to this display by typing ADDTCPPORT on any command line and pressing F4.

Chapter 2. TCP/IP: Operation, Management, and Advanced Topics 63