The DNS lookup for "monitor by hostname" is performed by the stack, not by WUG itself. The TTL is included in the reply... it's just not used. That's because the Windows DNS resolver is not caching the response. The DNS query is thus repeated on every poll.
Now, whilst there may be no caching on the WUG PC, there is caching in your local DNS server. And that is where the TTL comes into play... this DNS server will use the TTL to determine how long stuff stays in the cache. You might look at this and observe that some network traffic could be saved if WUG maintained its own DNS cache. That's true, but most WUG users monitor by IP and not Hostname. Or don't monitor enough devices by hostname that improving the underlying mechanics would make any noticable difference. Or, possibly, do have an issue but have never brought it to our attention. Mark Symons Ipswitch, Inc Augusta GA -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of James Amann Sent: Friday, February 13, 2004 09:25 To: [EMAIL PROTECTED] Subject: RE: [WhatsUp Forum] DNS Round Robin So the ttl is passed to wug by the dns during the lookup? >>> [EMAIL PROTECTED] 02/12/04 04:14PM >>> I put together this KB article a few months ago... http://support.ipswitch.com/kb/WG-20030613-DM02.htm Does it help? Is there a peculiarity of round robin not catered for in the article? As I recall, round robin uses TTL tweaks in order to achieve load balancing. And TTL is what the article is about. When you say "It appears however that WUG is "pinning" the first ip address after the first poll", are you sure that it is not switching to another IP at the end of the TTL? ie, did you wait long enough? Mark Symons Ipswitch, Inc Augusta GA -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of James Amann Sent: Thursday, February 12, 2004 08:56 To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: [WhatsUp Forum] DNS Round Robin I am trying to monitor a sit ethat has multiple servers behind it via a DNS round robin pool. My thought was to monitor via ICMP initially and poll by hostname. My thinking was that the polling would mimic the results a client might have if they were pinging the hostname. Fist time they would hit the first ip or server in the pool, second poll they would hit the second ip and so on. It appears however that WUG is "pinning" the first ip address after the first poll. That ip is then listed in the IP section of the detail sheet for the object and is the only ip to show up in the log. Can someone explain why this would be and if you have monitored similar resources, how have you done so? James McGovern Amann Network Technician Lead Georgia State University IST / UCCS 95 Decatur St. Suite 500 Atlanta, GA 30303 PH: 404.651.1574 FX: 404.651.4408 PG: 404.476.7754 Confidentiality Notice: This email message, including any attachments, contains information that is confidential and/or legally privileged. The information is intended only for the individual(s) named above. If you are not the intended recipient or the person responsible for delivering the email to the intended recipient, be advised that you have received this email in error and that any use, dissemination, distribution, forwarding, printing, or copying of this email is strictly prohibited. If you have received this email in error, please purge it immediately and notify the sender. Please visit http://www.ipswitch.com/support/mailing-lists.html to be removed from this list. An Archive of this list is available at: http://www.mail-archive.com/whatsup_forum%40list.ipswitch.com/
