DNS_EXPAND - UCMD Manager configuration option

Description

The DNS_EXPAND option specifies how many IP addresses are returned to UCMD Manager following a DNS query, which is issued to resolve a host name.

If the UCMD Manager is configured to expand the results of the query, all IP addresses defined for a particular host name are returned and expanded (in-place) within the list of hosts specified for the REMOTE_HOST option. Otherwise, only the first host is returned, and no expansion is performed.

For example, if a host list contains six host names, and the name in the 3rd position resolves to five IP addresses, those addresses will occupy positions 3-7 in the expanded list. Subsequent hosts specified by the user will begin at the 8th position in the expanded list.

That is:

  • If the REMOTE_HOST list contains:
    -host host1,host2,host3,host4,host5,host6
  • And host3 resolves to:
    ip3a, ip3b, ip3c, ip3d, and ip3e
  • Then after the other hosts are resolved, the list will be expanded to:
    -host ip1,ip2,ip3a,ip3b,ip3c,ip3d,ip3e,ip4,ip5,ip6

Usage

Method

Syntax

IBM i

UNIX

Windows

z/OS

Command Line, Short Form

n/a





Command Line, Long Form

-dns_expand option


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Environment Variable

UCMDDNSEXPAND=option

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Configuration File Keyword

dns_expand option

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STRUCM Parameter

DNSEXPAND(*option)

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Values

option specifies whether or not DNS query results are expanded.

Valid values for option are:

  • yes
    All IP addresses returned by a DNS for a given query are returned.
  • no
    Only the first IP address returned by a DNS for a given query is returned.

Default is no.