13.4.1 Host names and IP addresses
JP1/IM operates using the host name displayed by the hostname command or, in a cluster system, the specified logical host name.
When specifying a host name in a JP1/IM function, set the host name displayed by the hostname command or the logical host name.
Add the host name used by JP1/IM to the hosts file or other files, so that the name can be converted into an IP address.
If you are managing host names and IP addresses in the FQDN format by using the DNS, see 13.3.11 System configuration for managing monitored hosts with host names in FQDN format.
When specifying a logical host name, comply with the following conventions:
- Number of specifiable characters when not using the IM database:
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In Windows: 1 to 196 bytes (recommended: 63 bytes or less)
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In UNIX: 1 to 255 bytes (recommended: 63 bytes or less)
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- Number of specifiable characters when using the IM database:
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1 to 32 bytes
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If you are using any other host names, see 13.4.3 Operation in a configuration connected to multiple networks.
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When a host has multiple IP addresses, and a local host name is defined for each IP address in the hosts file, you can only specify the host name output by the hostname command as the Target host setting for an automated action.
An example is shown below.
Suppose that the following is defined in the hosts file:
100.0.0.10 hostA
200.0.0.10 hostB
If the host name displayed by the hostname command is hostA, you can only specify hostA as the target host name.
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The definition in the hosts file is not referred to for the host names and IP addresses that are defined in jp1hosts information or jp1hosts2 information.
An example is shown below.
Suppose that the following is defined in the jp1hosts information:
hostA 100.0.0.10 200.0.0.10
Suppose also that the following is defined in the hosts file:
100.0.0.10 hostA hostB
200.0.0.10 hostC
In this case, the hosts file is not referenced for hostA, IP address 100.0.0.10, or IP address 200.0.0.10. For this reason, you cannot specify hostB and hostC, which are not defined in the jp1hosts information, as target host names for command execution.
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Associations between the host names and IP addresses that are defined in jp1hosts or jp1hosts2 information must be the same as the corresponding definitions in the system. If you define an IP address different from the corresponding definition in the system, an inconsistency will occur in name resolution, and abnormal system operation will result.
Note the following points:
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Using DHCP
If the IP addresses used by JP1/IM and JP1/Base are managed using DHCP, set an unlimited duration for the IP address lease so that the IP address does not change.
JP1/IM and JP1/Base will not work properly if the IP address changes during JP1/IM and JP1/Base operation.
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Using a DNS server
Set the DNS server so that host names can be converted to IP addresses, and IP addresses can be converted to host names (reverse lookup). Note that when a DNS server (including Active Directory) is used for name resolution, you must purposely set JP1/IM to allow address lookup in both directions.