Managing TCP/IP Host Tables, Host File Formats

Managing TCP/IP Host Tables

In a large network, it can be more efficient to administer iSeries TCP/IP from a central site. Working with the host table would be time consuming if each system is individually updated with the TCP/IP configuration menu. Updates can be made more quickly on one system and then copied to others.

iSeries TCP/IP is designed to protect configuration files, including the host table. You cannot change the host table file unless you use the Configure TCP/IP menu or the MRGTCPHT, ADDTCPHTE, RNMTCPHTE, CHGTCPHTE, or RMVTCPHTE commands. However, you can still import and use a host table from a central site by using the MRGTCPHT command.

The following host table file types can be imported and merged with the server host table:

vHost table type *AS400, generated by iSeries TCP/IP Version 3 Release 1 Modification 0 (V3R1M0) or later

vHost table type *AIX, generated by iSeries TCP/IP Version 3 Release 0 Modification .5 (V3R0M5), Version 2 Release 3 (V2R3) or earlier, or many other IBM and non-IBM systems

vHost table type *NIC, host table format used by public domain systems

You can merge or replace the local server host table with the imported host table. The name of the database file containing the local host table is QATOCHOST with member HOSTS in library QUSRSYS. This file is used directly by iSeries TCP/IP; no conversion into an internal version takes place.

Host File Formats

If you receive a host file and want to use it on your system, the MRGTCPHT (Merge TCP/IP Host Table) command allows you to specify which format you are using. You can use host information files that are in either the *NIC format, the *AIX format, or the *AS400 format. The record length of the imported host table file is not limited.

Host Table Information with *AIX Files

Table 4 shows the *AIX format supported on the server.

Table 4. *AIX Supported on the AS/400 System

Delimiter	Meaning

# (pound sign)	Indicates the beginning of a comment. The text
	following the pound sign is a comment and is not part
	of the host table.

blank, tab	Indicates a field delimiter.

Host Table Information with *NIC Files

The *NIC format is often used by hosts in the public domain. A record in a *NIC file has the following format:

HOST : 128.12.19.1 : Host2.lan.ibm.com,Host2 : PC-AT : DOS : TCP/IP

This entry describes one host (at address 128.12.19.1) with two names (Host2.lan.ibm.com) and (Host2). The host is an IBM Personal Computer AT® computer running MS-DOS and supporting TCP/IP.

Chapter 2. TCP/IP: Operation, Management, and Advanced Topics 51