This doesn't answer your specific question but the search order is documented in the Communication Server IP configuration Guide. Here's what I found:
The resolver uses the IPv4-unique search order for sitename information unconditionally for getnetbyname API calls. The IPv4-unique search order for sitename information is as follows. The search ends at the first file found: 1. The value of the environment variable X_SITE The value of the environment variable is the name of the MVS data set that contains the sitename information. This data set is created by the TSOMAKESITE command. 2. /etc/hosts 3. userid.HOSTS.SITEINFO userid is the user ID that is associated with the current security environment(address space or task/thread). 4. hlq.HOSTS.SITEINFO hlq represents the value of the DATASETPREFIX statement specified in the base resolver configuration file (if found); otherwise, hlq is TCPIP by default. HTH, Rex -----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of [email protected] Sent: Thursday, March 12, 2020 9:59 AM To: [email protected] Subject: [External] HOSTNAMES on Z/OS TCPIP Hi,..I was previously on a Z/OS 2.2 system where I would update hostnames and IP Address in a Unix directory (/SYSTEM/etc/HOSTS) . When I transfered to a different division within the same company I am working on a z/OS 2.3 system, where Host Names and their associated IP Address's are stored in a Sequential File (TCP.HOSTNAME.LOCAL). . So here is my questions: How do I properly derive/navigate/determine if a System is using a USS directory or a MVS file to maintain its TCP HOST Names ? . Is this specified in UNIX System Services directory/configuration ? Is this specified in a TCPIP dataset ? Which Dataset ? Is this specidied in a RESOLVER dataset ? Which Dataset ?.Paul D'Angelo* . ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN The information contained in this message is confidential, protected from disclosure and may be legally privileged. If the reader of this message is not the intended recipient or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any disclosure, distribution, copying, or any action taken or action omitted in reliance on it, is strictly prohibited and may be unlawful. If you have received this communication in error, please notify us immediately by replying to this message and destroy the material in its entirety, whether in electronic or hard copy format. Thank you. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
