The FQDN names can be obtained from the FQDN file or from DNS.
Obtaining the FQDN name from the FQDN file
At BCAM system startup, the FQDN file is read in after the processor file. The FQDN file is searched for lines which contain both a BCAM processor name and an IP address. IP addresses and the associated processor names are entered in the processor file if they are both not yet known, or they are ignored if at least one of the two already exists. The FQDNs are ignored in this processing step.
When the FQDN file is processed, the processor file is accessed using an existing IP address. A corresponding entry must be found, and the following entries must match:
BCAM processor name of the line of the FQDN file which is currently being edited
BCAM processor name of the entry in the processor file which is found
The BCAM processor name is thus assigned the FQDN which is defined in the FQDN file, see also the section "FQDN file".
FQDNs whose computer label is longer than the eight characters of a valid processor name can thus be mapped to valid processor names.
Note
With the help of the FQDN file it is only possible to define DNS aliases using lines which have identical BCAM processor names.
Obtaining the FQDN name from DNS
During ongoing operation BCAM attempts to obtain DNS information (FQDN) on the known hosts and processors. A prerequisite here is that a DNS server which can be reached and which is known in BCAM is entered in the LWRESD configuration file.
When automatic end system creation takes place, the FDQNs are obtained by means of querying the DNS server in the case of (actively) initiated and (passively) accepted communication relationships.
In the cases mentioned the FQDNs are assigned to the hosts and processors.