ADDTCPHTE (Add TCP/IP Host Table Entry)

ADDTCPHTE Command syntax diagram

 

Purpose

The Add TCP/IP Host Table Entry (ADDTCPHTE) command adds an internet address and its associated host names along with an optional text description field to the local host table. For each entry, the host table is defined to allow one internet address, up to 4 host names, and a text description field.

If an internet address already exists in the host table that matches the internet address specified in the command, an escape message is sent to the user and the duplicate internet address is not added.

If a remote name server is being used by your iSeries 400 for resolving a host name or an internet address, the choice to first search the remote name server or the local host table depends on how the searched-first value was configured on the configuration panel of the remote name server. To change the remote name server or the searched-first value, enter the Configure TCP/IP (CFGTCP) command and select option 13.

The TCP/IP host table is shipped with the loopback entry. This entry has an internet address of 127.0.0.1 and two host names; LOOPBACK and LOCALHOST. The LOOPBACK host name can only be associated with an internet address that has a first-byte value equal to 127.

Related APPC over TCP/IP Information:

APPC over TCP/IP (part of the AnyNet/400* function) uses the host name to map location names to internet addresses. The host name must be in the form: 

location.netid.SNA.IBM.COM

Where location is the remote location the program is opening to, and netid is the network identifier for this connection. SNA.IBM.COM is the qualifier that designates this as the APPC over TCP/IP domain.

Location names support characters that cannot be present in host names (for example: $ (dollar), @ (at sign), and # (number sign)). Therefore, the APPC application can open only to locations that fulfill the TCP/IP host name syntax. This limits location names used for APPC over TCP/IP to the characters A-Z (uppercase and lowercase) and 0-9.

Restriction: You must have *IOSYSCFG special authority to use this command.

 

Required Parameters

INTNETADR
Specifies the internet address that the host names and text descriptions are associated with. The internet address is specified in the form nnn.nnn.nnn.nnn, where nnn is a decimal number ranging from 0 through 255. An internet address is not valid if it has a value of all binary ones or all binary zeros for the network identifier (ID) portion or the host ID portion of the address. If the internet address is entered from a command line, the address must be enclosed in apostrophes.

HOSTNAME
Specifies the host names corresponding to the internet address. The host name can be either the short form or the full domain version of the name. A common practice is to define one short name that is unique within your local network and to also define the full domain version of the host name that is unique within the internet. Specify from 1 to 4 different host names to be associated with the internet address.

A domain name or a host name can be a text string having 1 to 255 characters. Domain names consist of one or more labels separated by periods. Each label can contain up to 63 characters. The first character of each label must be an alphabetic character or a digit. The last character of each label must be an alphabetic character, a digit, or a period. The following characters are allowed in domain names:

  • Alphabetical characters A through Z

  • Digits 0 through 9

  • Underscore (_)

  • Minus sign (-)

  • Period (.). Periods are allowed only when they separate labels of the domain style name or as the last character in the domain name. (Refer to RFC 1034.) A domain name cannot have two consecutive periods.


Note: These characters are part of the Syntactic Character Set (character set number 640). This character set is also commonly referred to as invariant.

Other domain name and host name conventions include the following:

  • Uppercase and lowercase characters are allowed, but no significance is attached to the case. The host name (HOSTNAME) may be converted to uppercase depending on the combination of characters and digits. If the HOSTNAME is enclosed in apostrophes ('), the case is maintained as entered.

  • The host name returned when searching the host table for an internet address is the first host name associated with the internet address. For example, if the address 9.130.38.187 is defined in the host table with names ROCHESTER, JOHN, and RCHAS100, the name ROCHESTER would be returned. The other two host names would not be used in this type of search. However, these host names would be used when searching the host table to find the internet address associated with the names JOHN and RCHAS100.

  • Try to limit your domain name labels to 12 characters. Shorter labels are easier to remember.

  • It is a common practice to use hierarchical names that allow predictable extensions for change and growth. Domain names normally reflect the delegation of authority or hierarchy used to assign them.

    For example, the name SYS1.MFG.ABC.COM can be broken down into the following:

    COM
    All commercial networks.
    ABC.COM
    All systems in the ABC company's commercial network.
    MFG.ABC.COM
    All manufacturing systems in the ABC company's commercial network.
    SYS1.MFG.ABC.COM
    A host named SYS1 in the manufacturing area of the company's commercial network.

    The COM designation is one of several domain names used by convention when connecting to the Internet. Some of the other domain names that follow this convention are:

    COM
    Commercial organizations
    EDU
    Educational institutions
    GOV
    Government institutions
    MIL
    Military groups
    NET
    Major network support centers
    ORG
    Organizations other than those listed previously
    ARPA
    Temporary ARPANET domain
    Country or region code
    Countries other than USA

host-name: Specify a host name to be associated with the specified internet address. When running APPC over TCP/IP, name is in the form: 

location.netid.SNA.IBM.COM

The default if a host name is not specified is blanks. At least one host name must specified. An IP address cannot be a host name.

 

Optional Parameters

TEXT
Specifies a comment associated with this host table entry.

Note: If the host table will be copied to a system using a different code page than the system it was created on, it is suggested that you avoid using certain characters in a comment. Host table entry comments will be more portable if they are limited to characters in the Syntactic Character Set (invariant).

*BLANK: The text-description field for this host table entry is to contain blanks.

'description': Specify a text-description field to be associated with the specified internet address. Comments can contain a maximum of 64 characters.

Examples for ADDTCPHTE

Example 1: Adding a Short Host Name 

ADDTCPHTE   INTNETADR('132.28.71.5')
  HOSTNAME(AS400ETH)
  TEXT('iSeries 400 on Ethernet subnet')

This command associates the host name AS400ETH with the internet address of 132.28.71.5. The text 'iSeries 400 on Ethernet subnet' is saved as the descriptive comment for this host table entry.

Example 2: Adding Two Host Names 

ADDTCPHTE   INTNETADR('9.5.42.6')
  HOSTNAME((AS400ETH.SALES.ABC.COM)
           ('as400eth.sales.abc'))
  TEXT('Entry verified on 1 April 1994 by J. Jones')

This command associates the host names AS400ETH.SALES.ABC.COM and AS400ETH.SALES.ABC with the internet address of 9.5.42.6. Because no significance is attached to a case, a match is found on host name AS400ETH.SALES.ABC.COM or as400eth.sales.abc. The text 'Entry verified on 1 April 1994 by J. Jones' is saved as the descriptive comment for this host table entry.

Error messages for ADDTCPHTE

*ESCAPE Messages

TCP1901
Internet address &1 not valid.
TCP1902
Internet address &1 not valid.
TCP1903
Specified host name not valid.
TCP1904
Duplicate internet address &1 found in host table.
TCP1908
Internet address &1 not valid.
TCP1910
LOOPBACK internet address &1 not valid.
TCP1929
Host table not available.
TCP9999
Internal system error in program &1.