The description below is from my notes. -Rick
Excerpts from the AIX manuals:
Three environment variables affect values related to the _res structure:
LOCALDOMAIN Overrides the default local domain, which is read from the
/etc/resolv.conf file and stored in the defdname field of the _res structure. RES_TIMEOUT Overrides the default value of the retrans field of the _res
structure, which is the value of the RES_TIMEOUT constant defined in the
/usr/include/resolv.h file. This value is the base time-out period in seconds
between queries to the name servers. After each failed attempt, the time-out
period is doubled. The time-out period is divided by the number of name servers
defined. The minimum time-out period is 1 second.RES_RETRY Overrides the default value for the retry field of the _res structure,
which is 4. This value is the number of times the resolver tries to query the
name servers before giving up. Setting RES_RETRY to 0 prevents the resolver from
querying the name servers.
The default for RES_TIMEOUT is 5 seconds.
If one inserts a bogus address at the top of the DNS server list in /etc/resolv.conf, one gets a five second delay in DNS lookups. Given the default values specified by the AIX documentation, this indicates that AIX behaves the same way the someone told me Solaris behaves - if the first address times out, it tries the second address, then the third, etc. Then it goes back and tries them all again until it has tried the whole list RES_RETRY times. This is a good algorithm - not like I originally thought.
If I "setenv RES_TIMEOUT 1", then I get only a one second delay in DNS lookups with the bogus address. This is much better.
Patrick Powell wrote:
From [EMAIL PROTECTED] Tue Jul 13 15:48:20 2004 Date: Mon, 12 Jul 2004 15:07:26 -0500 From: Russell Adams <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Subject: LPRng: DNS Resolution Issue
I recently had a problem on AIX with LPRng 3.8.26 where printing commands hung for up to ten minutes before printing, querying status, etc.
Even doing an "lpq --help" hung! That shouldn't involve any remote queries...
The situation was that one of our DNS servers had stopped responding to queries (still up, but service died). The primary DNS server and another secondary were still available.
The problems with LPRng persisted until we restarted the DNS service, however AIX and our other software products didn't have problems resolving names during that time period.
Does LPRng use a custom resolve library or another unusual method for lookups? I'm trying to figure out why LPRng responded that way when there were other DNS servers available.
This is odd.
Check the output of the configure facility and see what libraries it is using.
I suspect that part of the problem might be that you did not have the other DNS servers listed in the /etc/resolv.conf file.
By the way, I really recommend using a local DNS server in caching mode. You can then have:
/etc/resolv.conf:
nameserver 127.0.0.1 search your.local.domain
In /etc/namedb/named.conf (or whereever the named configuration is):
options { forwarders { 10.0.0.2; }; <<< put the IP ADDRESSES of your DNS servers here directory "/etc/namedb"; pid-file "/var/run/named/pid";
Russell
You will find that your performance and reliability will greatly increase.
Patrick Powell Astart Technologies [EMAIL PROTECTED] 6741 Convoy Court Network and System San Diego, CA 92111 Consulting 858-874-6543 FAX 858-751-2435 LPRng - Print Spooler (http://www.lprng.com)
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If you have major problems, call Patrick Powell or one of the friendly staff at Astart Technologies for help. Astart also does support for LPRng. Also, check the Web Page at: http://www.lprng.com for any announcements. Astart Technologies (LPRng - Print Spooler http://www.lprng.com) 6741 Convoy Court San Diego, CA 92111 858-874-6543 FAX 858-751-2435 -----------------------------------------------------------------------------
-- |Rick Cochran phone: 607-255-7618| |Cornell CIT - Systems & Operations - Net-Print FAX: 607-255-8521| |730 Rhodes Hall, Ithaca, N.Y. 14853 email: [EMAIL PROTECTED]|
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If you have major problems, call Patrick Powell or one of the friendly staff at Astart Technologies for help. Astart also does support for LPRng. Also, check the Web Page at: http://www.lprng.com for any announcements. Astart Technologies (LPRng - Print Spooler http://www.lprng.com) 6741 Convoy Court San Diego, CA 92111 858-874-6543 FAX 858-751-2435 -----------------------------------------------------------------------------
