Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.
Buying anything on Amazon? Please use the Geekzone Amazon aff link.




546 posts

Ultimate Geek
+1 received by user: 31

Subscriber

Topic # 87331 26-Jul-2011 09:45 Send private message

Howdy,

So my problem is that the application I support is suddenly taking 12s to return a hostname for a given IP.  Prior to D day, it was taking a more acceptable 1-5s.  I've got the task of convincing IT its their network thats changed as opposed to our application.

I imagine its a fairly typical Win2003 domain (don't have sys admin rights so can't nose about) with Windows running the DNS and DHCP.
Using nslookup tells me that there are no Reverse Lookup zones configured (i.e 2s timeout when querying by IP)
On the server NICs there's no defined WINS server, LMHosts lookup is not enabled and NetBIOS is set to "Default-Use NetBIOS settings from the DHCP server". 
There are no Host file entries on any of the servers.
Server dns and arp caches have been flushed.

The connecting clients have a mixture of both static and dynamic IPs

My questions is, how does reverse lookup even happen in this type of environment anyway?

Create new topic
7778 posts

Uber Geek
+1 received by user: 326

Trusted
Subscriber

  Reply # 497926 26-Jul-2011 11:02 Send private message

Does nbstat -c or nbstat -r (start > run > cmd > nbstat ?) give you any useful info?



546 posts

Ultimate Geek
+1 received by user: 31

Subscriber

  Reply # 498023 26-Jul-2011 13:54 Send private message

Ragnor: Does nbstat -c or nbstat -r (start > run > cmd > nbstat ?) give you any useful info?


Brilliant, thanks for that.

Running nbtstat -c regularly is showing the netbios cache is being updated, which seems to be the only source of reverse lookups.
-r is shows that the vast majority of resolutions are being done by Broadcast which'll explain the increased times in the app logs.

So I wonder what could change on a network to go from an average of 3s resolution to over 12s?? 

Create new topic




Twitter »
Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





Trending now »

Hot discussions in our forums right now:

Has Spark (Telecom) locked their iphone 6 ?
Created by anewguy2014, last reply by michaelmurfy on 17-Dec-2014 14:32 (25 replies)
Pages... 2


Police Camera Van Disguise
Created by Reanalyse, last reply by scuwp on 21-Dec-2014 12:16 (71 replies)
Pages... 3 4 5


Do I have the right to return this?
Created by corksta, last reply by alasta on 21-Dec-2014 12:59 (44 replies)
Pages... 2 3


In defence of cats
Created by Rikkitic, last reply by DarthKermit on 17-Dec-2014 15:40 (68 replies)
Pages... 3 4 5


Slaughter of Innocents
Created by networkn, last reply by networkn on 19-Dec-2014 17:46 (64 replies)
Pages... 3 4 5


Crew Drinking on Flights - Why!?
Created by networkn, last reply by gzt on 21-Dec-2014 13:38 (20 replies)
Pages... 2


Spray Foam Insulation
Created by AACTech, last reply by timbosan on 19-Dec-2014 16:58 (36 replies)
Pages... 2 3


How to upload 150GB of photos to iCloud?
Created by josephhinvest, last reply by timbosan on 17-Dec-2014 15:05 (35 replies)
Pages... 2 3



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.

Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.