Hi Chris, First of all, very appreciate your kindly and very speific explaination! I read through the document you mentioned. If I let resolver with default settings, there will be no global tcpip data and default tcpip data.. According to the search order, the tcpip will use //SYSTCPD DD card as its tcpdata source...
So I only define the relative settings in the member of //SYSTCPD DD card refers to.. I defined the HOSTNAME ABC, LOOKUP LOCAL. But when I issued HOMETEST, it couldn't get the hostname of ABC.. in shew hostname as NODENAME, so the resolving failed. However, I can use TESTSITE to resolve the hostname ABC. Best Regards! Anson ________________________________ From: Chris Mason <[email protected]> To: [email protected] Sent: Saturday, July 23, 2011 12:33 AM Subject: Re: TCPIP Resolver Question Anson You will find the greatest concentration of expertise with the IP component of z/OS Communications Server (CS) in the following list: For IBMTCP-L subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBMTCP-L There are also specialists in "TCP/IP for VM" to be found there if that is ever a concern for you. > Now comes out the question, what's the 'applicable searching order'? I think you may need to refresh your memory of the z/OS CS IP class you took and then read up on the following chapter in the z/OS CS IP Configuration Guide manual: 2.5 Chapter 14. The resolver http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/F1A1B3A0/2.5 Note that you can skip the relatively recently introduced functions described under "2.5.8 Resolver functions" for now. Once you have read through - and understood - the "2.5.9 Resolver configuration files" section, - I think - your initial question will be answered. I say "I think" since the text string "applicable searching order" can be found neither in the z/OS CS IP Configuration Guide not the z/OS CS IP Configuration Reference manual. It's always much the best policy to give a manual reference as I do above - and as Don Poitras did - when you want an explanation on anything specific. - If you do not create a RESOLVER procedure, in effect, z/OS creates one for you using the IEESYSAS procedure. This is a general purpose procedure which can start any program quite happily just so long as it doesn't need any DD-statements associated with it. In addition, the started task name can slyly be named by using the "trick" on the START command which sets up a name other than the name under which the procedure - in this case IEESYSAS - is stored in the typically SYS1.PROCLIB partitioned data set. Thus, the resolver setup parameters you use necessarily have only the default values. See the following: 5.0 Chapter 5. Resolver setup and TCPIP.DATA configuration statements http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/F1A1B4A0/5.0 The "search order" for the generically named TCPIP.DATA data set is the following: For a program using the "z/OS UNIX" environment: GLOBALTCPIPDATA The value of the environment variable RESOLVER_CONFIG /etc/resolv.conf //SYSTCPD DD card userid.TCPIP.DATA SYS1.TCPPARMS(TCPDATA) DEFAULTTCPIPDATA TCPIP.TCPIP.DATA For a program using the "MVS" environment: GLOBALTCPIPDATA //SYSTCPD DD card userid/jobname.TCPIP.DATA SYS1.TCPPARMS(TCPDATA) DEFAULTTCPIPDATA TCPIP.TCPIP.DATA Because you have elected not to set up a customised RESOLVER procedure, necessarily any data set named by the GLOBALTCPIPDATA and DEFAULTTCPIPDATA resolver setup statements cannot feature in the "search order" you will be using. Note that you are not going to get very far with the IP component of z/OS CS unless you get familiar with this thorny topic of "search order". These "search orders" - which are universal throughout all z/OS CS IP components - offer great flexibility but are a snare for novices. In essence they are there because of the heritage of z/OS CS IP. z/OS CS IP migrated from "TCP/IP for MVS" - initially as OS/390 CS IP - and "TCP/IP for MVS" was a "port" of "TCP/IP for VM" which was created because IBM woke up to the fact that the world was really quite keen on IP-related protocols for networking purposes and actually not really all that keen on OSI protocols - assuming the world wasn't happy just to plod along with SNA! Incidentally, I've no idea where Don Poitras got his "normally" from! Perhaps SYS1.TCPPARMS(TCPDATA) is just what his installation happens to use by preference. I hear of many installations which absolutely swear by the use of the SYSTCPD DD-statement whereas I'll bet that there are many out there which rub along with TCPIP.TCPIP.DATA because, if it was good enough for my grandfather, it's good enough for me! I've just realised that wherever you found that "applicable searching order", very probably the "applicable" refers to having to decide whether the program which needs the services of the resolver function uses the "z/OS UNIX" environment or the "MVS" environment. Saying which of these environments "applies" in the case of each program which uses the services of the main CS IP address space is something at which IBM authors, say of the z/OS CS IP manuals, are not particularly good. And then there's the matter of whether vendor program authors are any good at it either ... You have my permission to be very rude to any one of them whenever it is not clear and perhaps shame will have the desired effect - one can always hope ... Incidentally, for what it's worth, the main CS IP address space abides by the rules which apply to the "z/OS UNIX" environment. See "1.2.6.2 TCPIP.DATA search order". http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/f1a1b3a0/1.2.6.2 Chris Mason On Fri, 22 Jul 2011 04:55:58 -0700, Anson Ye <[email protected]> wrote: >Hi All, I'm reading some tcpip document about resolver.. I'm curious what system will do if I don't configure the resolver settings explicitly. According to the IBM book library, if I don't specify the resolver process in the BPXPRMxx, the system will start up the resolver address apce with name of 'RESOLVER' but without global tcpip data settings. The z/OS will use the applicable searching order for finding TCPIP.DATA. Now comes out the question, what's the 'applicable searching order'? Thanks! Best Regards! Anson ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
