2.11.4 Notes on communication protocols of JP1/Base

JP1/Base recognizes the host name when communicating with a host. When running on a physical host, JP1/Base recognizes, as the local host name, the host name returned by the hostname command. When running on a logical host, JP1/Base recognizes, as the local host name, the logical host name specified in the settings for the cluster system. Note, therefore, the following:

• Use one representative host name and avoid use of several alias names.

• JP1/Base does not operate properly if the IP address assigned to a host name cannot be resolved.

• You must set up an environment that allows for both the conversion from a host name to an IP address and the conversion from an IP address to a host name. Setting the bi-directional conversion indicated above is necessary especially for resolving names on a DNS server (including Active Directory).

• In an environment with multiple LAN connections where a host name resolves to multiple IP addresses, JP1/Base uses the IP address with the highest priority for the host name.

• If JP1/Base uses the IP binding method for sending, the IP address with the highest priority for the local host name is used as the source IP address.

• A communication failure occurs when a non-loop-back address attempts to connect to a loop-back address or vice versa, even if the non loop-back address is an address within a same host. Therefore, a loop-back address cannot be used to operate JP1/Base. In addition, no host name that becomes a loop-back address as a result of address resolution can be used.

• If JP1/Base is using the IP address and host name that are defined in the hosts file, make sure the combination of IP address and host name is not duplicated.

• In Linux, in an environment that uses JP1/Base, do not set net.ipv4.ip_nonlocal_bind to 1. If net.ipv4.ip_nonlocal_bind is set to 1, profile collection by JP1/IM Configuration Management fails. The setting of net.ipv4.ip_nonlocal_bind can be checked by using the sysctl command.

  # sysctl net.ipv4.ip_nonlocal_bind

  If net.ipv4.ip_nonlocal_bind is set to 1, follow one of the following procedures:

  • Delete this parameter from /etc/sysctl.conf, and then restart the system or execute "sysctl -w net.ipv4.ip_nonlocal_bind=0", and then restart JP1/Base and the JP1 programs for which JP1/Base is a prerequisite.

  • Change the setting in /etc/sysctl.conf to "net.ipv4.ip_nonlocal_bind=0", execute the "sysctl -p" command, and then restart JP1/Base and the JP1 programs for which JP1/Base is a prerequisite.

• JP1/Base cannot be used in an environment where a unique host name or IP address cannot be resolved from the host name at communication with the server. For this reason, JP1/Base does not support dynamic NAT (in which the host is assigned an address available at the time, and rules are set and changed automatically). Nor does JP1/Base support NAPT containing port translations (IP Masquerade and NAT+).

• Using DHCP

  If the IP addresses used by JP1/Base are managed using DHCP, set an unlimited duration for the IP address lease so that the IP address does not change.

  JP1/Base will not work properly if the IP address changes during JP1/Base operation.

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