Change TCP/IP Domain (CHGTCPDMN)

Where allowed to run: All environments (*ALL)
Threadsafe: No
Parameters
Examples
Error messages

The Change TCP/IP Domain (CHGTCPDMN) command is used to specify this system's TCP/IP host and domain name and to configure the Domain Name Server (DNS) information for this system.

Restrictions:

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Parameters

Keyword Description Choices Notes
HOSTNAME Host name Character value, *SAME, *NONE Optional
DMNNAME Domain name Character value, *SAME, *NONE Optional
DMNSCHLIST Domain search list Character value, *SAME, *DFT Optional
HOSTSCHPTY Host name search priority *REMOTE, *LOCAL, *SAME Optional
INTNETADR Domain name server Element list Optional
Element 1: Internet address Character value, *SAME, *NONE
Element 2: Internet address Character value, *SAME, *NONE
Element 3: Internet address Character value, *SAME, *NONE
PORT Port 1-65535, *SAME Optional
PROTOCOL Protocol *UDP, *TCP, *SAME Optional
INLDMNSVR Initial domain name server *FIRST, *ROTATE, *SAME Optional
DMNSVRRTY Domain name server retry Element list Optional
Element 1: Number of retries 1-99, *SAME
Element 2: Initial time interval 1-99, *SAME
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Host name (HOSTNAME)

Specify the TCP/IP host name of this system.

Note: This system's TCP/IP host name must also be defined in the local host table or the Domain Name Server (DNS) specified in the INTNETADR parameter. If no DNS is specified, the local TCP/IP host table is used.

*SAME
The TCP/IP host name does not change if it was previously set.
*NONE
No host name is defined for this system.
character-value
Specify a TCP/IP host name for this system. The host name is a text string that has 1 to 63 characters. The following characters are allowed in the host name:
  • Alphabetical characters A through Z
  • Digits 0 through 9
  • Underscore (_)
  • Minus sign (-)

The first and last characters of the host name must be an alphabetical character or a digit.

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Domain name (DMNNAME)

Specify the name of the TCP/IP domain this host is a member of.

*SAME
The TCP/IP domain name does not change if it was previously set.
*NONE
No TCP/IP domain name is defined for this system.
character-value
Specify the TCP/IP domain name for this system. The domain name consists 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 alphabetical character or a digit. The last character of each label must be an alphabetical character, a digit, or a period. The following characters are allowed in the domain name:
  • Alphabetical characters A through Z
  • Digits 0 through 9
  • Underscore (_)
  • Minus sign (-)
  • Period (.). Periods are allowed only when they separate domain name labels or as the last character in the domain name (refer to RFC 1034). A domain name cannot have two consecutive periods.

The DMNNAME parameter combined with the HOSTNAME parameter must be less than 255 characters in length.

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Domain search list (DMNSCHLIST)

Specify the TCP/IP domains to search when fully-qualified domain names (FQDN) are not given. The first name in the search list is the default domain name on all searches.

*SAME
The domain search list does not change if it was previously set; otherwise *DFT is used.
*DFT
The default behavior is to search the local domain tree. The local domain tree is the system TCP/IP domain name (DMNNAME) and each parent domain with two or more parts to the domain. The system TCP/IP domain name is the default domain name on all searches.
character-value
Specify the list of domain names to be searched. Each domain name must follow the criteria specified for the DMNNAME parameter. Up to six domain names may be specified, separated by spaces and enclosed in apostrophes. The maximum length for the DMNSCHLIST parameter is 256 characters. The first domain name in the search list is the default domain name on all searches. Note that if a domain search list is defined then the local system TCP/IP domain name (DMNNAME) will not automatically be used in the search list. Parent domains for the domains defined in the search list will not be searched. If you want parent domains to be searched then they must be explicitly defined in the search list.
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Host name search priority (HOSTSCHPTY)

Specifies whether to search a Domain Name Server (DNS) first to resolve a TCP/IP host name conflict, or to search the local TCP/IP host table first.

*SAME
The value does not change if it was previously set. If the value was not previously set, *REMOTE will be used.
*REMOTE
Specify *REMOTE if you want this system to search a remote or local DNS to resolve TCP/IP host names before searching the local TCP/IP host table. The DNS to use is specified by the internet address (INTNETADR) parameter.
*LOCAL
Specify *LOCAL if you want this system to first search the TCP/IP host table, located on this system, to resolve TCP/IP host names.
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Internet address (INTNETADR)

Specifies up to three Domain Name Servers (DNS) to be used by this system. Specify a DNS by entering its internet address. You may add none, one, two, or three DNS internet addresses.

If the first DNS in the list does not respond, the second DNS server in the list will be contacted. If the second DNS server does not respond, the third DNS server will contacted.

A DNS IPv4 internet address is specified in the form nnn.nnn.nnn.nnn, where nnn is a decimal number ranging from 0 through 255.

An IPv6 internet address is specified in the form x:x:x:x:x:x:x:x, where x is a hexadecimal number ranging from 0 through X'FFFF'. "::" may be used once in the IPv6 address to indicate one or more groups of 16 bits of zeros. The "::" may be used to compress leading, imbedded, or trailing zeros in the address.

An IPv4-mapped IPv6 address may be specified. An IPv4-mapped IPv6 address is specified in the form ::FFFF:nnn.nnn.nnn.nnn, where nnn is a decimal number ranging from 0 through 255.

Element 1: Internet address

*SAME
The value does not change.
*NONE
No domain name server address is specified.
character-value
Specify the internet address of a domain name server.

Element 2: Internet address

*SAME
The value does not change.
*NONE
No domain name server address is specified.
character-value
Specify the internet address of a domain name server.

Element 3: Internet address

*SAME
The value does not change.
*NONE
No domain name server address is specified.
character-value
Specify the internet address of a domain name server.
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Port (PORT)

Use this parameter to specify the remote TCP/IP port number used to contact the Domain Name Server (DNS) or Servers listed in the INTNETADR parameter. 53 is the well-known port used for this purpose.

Note: Use of a TCP/IP port number other than the well-known port 53 for use by the Domain Name Server (DNS) can result in TCP/IP communication problems. You may inadvertently use a port number which is reserved for use by another TCP/IP application.

*SAME
The remote port number will not be changed if it was previously set. If the remote port number was not previously set, the remote port number 53 will be used.
1-65535
Specify the remote port number to be used to contact the Domain Name Server (DNS) specified in the INTNETADR parameter.
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Protocol (PROTOCOL)

Specify the TCP/IP protocol used to communicate with the Domain Name Server (DNS) specified in the INTNETADR parameter. User Datagram Protocol (UDP) is typically used for this purpose. Use *TCP only if your Domain Name Server (DNS) is specifically configured to use the Transmission Control Protocol (TCP).

*SAME
The protocol value will not be changed if it was previously set. If the protocol value was not previously set, the protocol value *UDP will be used.
*UDP
Specifies use of the User Datagram Protocol (UDP) to communicate with the Domain Name Server (DNS) specified in the INTNETADR parameter.
*TCP
Specifies the use of Transmission Control Protocol (TCP) to communicate with the Domain Name Server (DNS) specified in the INTNETADR parameter.
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Initial domain name server (INLDMNSVR)

Specify the initial domain name server selection method. This option determines whether the first configured Domain Name Server (DNS) should always be queried first, or if the first name server to be queried should be rotated in a round robin fashion if more than one is configured. This rotation provides a simple form of load balancing on the configured name servers.

*SAME
The initial domain name server selection value will not be changed if it was previously set. If the initial domain name server selection value was not previously set, the value *FIRST will be used.
*FIRST
The first configured domain name server is queried first. Always query the Domain Name Servers (DNS) in order as configured.
*ROTATE
Rotate through the configured name servers in a round robin fashion to determine which to query first.
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Domain name server retry (DMNSVRRTY)

The Domain Name Server Retry (DMNSVRRTY) parameter consists of two elements: number of retries and initial time interval.

Number of retries specifies the number of additional attempts made to establish communication with each Domain Name Server (DNS) specified in the INTNETADR parameter in the event that the first attempt fails.

Initial time interval specifies the initial interval in seconds between retries. For each subsequent retry attempt, the time interval is doubled to a maximum of 120 seconds. For example, if number of retries is 4 and initial time interval is 2, the first retry would occur 2 seconds after the initial attempt to contact the DNS. The second retry would occur 4 seconds after the first retry, the third retry occurs 8 seconds after the second retry, and the fourth retry occurs 16 seconds after the third retry.

Element 1: Number of retries

*SAME
This is the default value. The number of retries value will not be changed if it was previously set. If the number of retries value was not previously set, the value of 2 will be used.
1-99
Specify the number of communication retry attempts.

Element 2: Initial time interval

*SAME
The initial time interval value will not be changed if it was previously set. If the initial time interval value was not previously set, the value of 2 will be used.
1-99
Specify the initial time interval in seconds.
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Examples

Example 1: Change Host and Domain Names

CHGTCPDMN   HOSTNAME(rs021)  DMNNAME(endicott.ibm.com)

This command changes the host name and domain name.

Example 2: Change Domain Search List

CHGTCPDMN   DMNSCHLIST('endicott.ibm.com
                        rochester.ibm.com
                        ibm.com')

This command changes the domain search list to be three domain names: endicott.ibm.com, rochester.ibm.com, and ibm.com.

Example 3: Change Domain Name Servers

CHGTCPDMN   INTNETADR('9.131.42.251' '5678::1234' *NONE)

This command specifies two domain name server addresses: 9.131.42.251 and 5678::1234.

Example 4: Change Domain Name Server Rotation

CHGTCPDMN   INLDMNSVR(*ROTATE)

This command changes the initial domain name server selection so it rotates between the configured name servers in a round robin fashion.

Example 5: Change Domain Name Server Retry

CHGTCPDMN   DMNSVRRTY(3 10)

This command changes the domain name server retry values. It sets the number of retries to three and the interval between each retry to ten seconds.

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Error messages

*ESCAPE Messages

TCP1609
TCP/IP domain information not changed.
TCP264D
Error occurred processing file.
TCP8050
*IOSYSCFG authority required to use &1.
TCP9503
File &3 in library &2 not available.
TCP9999
Internal system error in program &1.
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