nixCraft Linux Forum

nixCraft

Linux / UNIX Tech Support Forum

Slow resolutions from DNS server

This is a discussion on Slow resolutions from DNS server within the CentOS / RHEL / Fedora forums, part of the Linux Distribution category; Hi all, I am facing an issue with DNS server.. I am seeing slow resolutions from our Public DNS servers.. ...


Go Back   nixCraft Linux Forum > Linux Distribution > CentOS / RHEL / Fedora

Linux answers from nixCraft.


CentOS / RHEL / Fedora Discussion about Redhat Enterprise Linux or CentOS or Fedora Linux related problems.

Reply

 

LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 18-11-2009, 11:16 AM
kumarat9pm's Avatar
Senior Member
User
 
Join Date: Jun 2007
Location: Pune,MH,India
OS: RHEL,UBUNTU..
Posts: 442
Thanks: 20
Thanked 20 Times in 18 Posts
Rep Power: 5
kumarat9pm has a spectacular aura about kumarat9pm has a spectacular aura about kumarat9pm has a spectacular aura about
Send a message via Yahoo to kumarat9pm Send a message via Skype™ to kumarat9pm
Default Slow resolutions from DNS server

Hi all,

I am facing an issue with DNS server.. I am seeing slow resolutions from our Public DNS servers.. how to resolve this issue?
i know one issue is.. if there is no reverse lookup zone file is not there on server this type of problems we will be facing..
Note:reverse lookup zones files for this dns server is with ISP..
is it mandatory not to configure reverse lookup zone files on server and giving them to ISP?
i am bit confused please share your thoughts/inputs how to resolve this issue.
Can we see any logs of dns servers in any file other then /var/log/messages?
__________________
Thanks,
Surendra Kumar Anne
Ubuntu: Simple, Stylish and Striking..!
Linux: Fast, friendly, flexible and .... free!
Support Open source.
Reply With Quote
  #2 (permalink)  
Old 19-11-2009, 05:21 AM
jaysunn's Avatar
Powered By Linux
User
 
Join Date: Apr 2009
Location: 41.332032,-73.089775
OS: RHEL - OSX
Posts: 600
Thanks: 61
Thanked 78 Times in 70 Posts
Rep Power: 10
jaysunn is a splendid one to behold jaysunn is a splendid one to behold jaysunn is a splendid one to behold jaysunn is a splendid one to behold jaysunn is a splendid one to behold jaysunn is a splendid one to behold jaysunn is a splendid one to behold jaysunn is a splendid one to behold
Default

Hey kumarat9pm,

I just went through trying to find log files other than /var/log/messages today.

On RHEL, you can run

Code:
/etc/init.d/named status

Or play with the file /etc/named.conf

Code:
logging {
        category security { default_syslog; };
        category lame-servers { null; };
        category queries { null; };
};
I know there is a way to open this up to more debugging options. I have mine set to null, however you can change this. Have a look at changing the logging on BIND and make sure you restart named when you make the changes.

Also have a look at these tools:

Code:
[root@dns1 ~]# named
named            named-bootconf   named-checkconf  named-checkzone
And this link:

Check BIND – DNS Server configuration file for errors with named-checkconf tools



HTH,

Jaysunn
__________________
Have a look at what I have been working on
http://www.shellasaurus.com
Reply With Quote
The Following User Says Thank You to jaysunn For This Useful Post:
kumarat9pm (19-11-2009)
  #3 (permalink)  
Old 19-11-2009, 06:33 AM
kumarat9pm's Avatar
Senior Member
User
 
Join Date: Jun 2007
Location: Pune,MH,India
OS: RHEL,UBUNTU..
Posts: 442
Thanks: 20
Thanked 20 Times in 18 Posts
Rep Power: 5
kumarat9pm has a spectacular aura about kumarat9pm has a spectacular aura about kumarat9pm has a spectacular aura about
Send a message via Yahoo to kumarat9pm Send a message via Skype™ to kumarat9pm
Default thanks for the reply jay..

Ya may be that is true to get more info on named.conf file logging.. will try to get some more info on this.. and the mention syntax checking commands will not help me any thing bcz all ready my DNS server is working fine expect slow resolutions..
__________________
Thanks,
Surendra Kumar Anne
Ubuntu: Simple, Stylish and Striking..!
Linux: Fast, friendly, flexible and .... free!
Support Open source.
Reply With Quote
  #4 (permalink)  
Old 19-11-2009, 10:50 AM
nixcraft's Avatar
Never say die
User
 
Join Date: Jan 2005
Location: BIOS
OS: RHEL
Scripting language: Bash and Python
Posts: 2,709
Thanks: 11
Thanked 244 Times in 183 Posts
Rep Power: 10
nixcraft has a reputation beyond repute nixcraft has a reputation beyond repute nixcraft has a reputation beyond repute nixcraft has a reputation beyond repute nixcraft has a reputation beyond repute nixcraft has a reputation beyond repute nixcraft has a reputation beyond repute nixcraft has a reputation beyond repute nixcraft has a reputation beyond repute nixcraft has a reputation beyond repute nixcraft has a reputation beyond repute
Default

Reverse zone belongs to people who control IP address. If ip address leased from ISP, they will control reverse zone. For example, nixcraft.com is resolved by ns{1,2}.nixcraft.net. But its ip reverse lookup is 75.126.168.152 is done by ISP name servers as IP belongs to them.

As far as speed turn on debugging as suggested by above poster. Another geeky and recommend option is to run tcpdump on # 53 and see what is going on.
__________________
Vivek Gite
Linux Evangelist
Be proud RHEL user, and let the world know about your enterprise choices! Join RedHat user group.
Always use CODE tags for posting system output and commands!
Do you run a Linux? Let's face it, you need help
Reply With Quote
  #5 (permalink)  
Old 23-11-2009, 11:01 AM
kumarat9pm's Avatar
Senior Member
User
 
Join Date: Jun 2007
Location: Pune,MH,India
OS: RHEL,UBUNTU..
Posts: 442
Thanks: 20
Thanked 20 Times in 18 Posts
Rep Power: 5
kumarat9pm has a spectacular aura about kumarat9pm has a spectacular aura about kumarat9pm has a spectacular aura about
Send a message via Yahoo to kumarat9pm Send a message via Skype™ to kumarat9pm
Default Thanks for your enligtment Nix..

Here the problem is on Firewall of my company..
we have 2 NS server. ns1 is properly mapped to the name server one, where as ns2 is mapped to one of the ftp severs .. so its unable to resolve the hostnames.. now we changed the mappings to proper DNS servers.. now its working like charm..
Thanks once again..
__________________
Thanks,
Surendra Kumar Anne
Ubuntu: Simple, Stylish and Striking..!
Linux: Fast, friendly, flexible and .... free!
Support Open source.
Reply With Quote
Reply

Tags
bind , debug , dns , firewall , linux , named , nameservers , ns1 , ns2 , port 53


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads

Thread Thread Starter Forum Replies Last Post
"tar xvf" command is executing very slow prahladkumar CentOS / RHEL / Fedora 0 02-04-2009 03:44 PM
Slow arp and route output - network issue? sserye Networking, Firewalls and Security 3 15-10-2008 11:12 PM
Running script is very slow!!! JATA01 CentOS / RHEL / Fedora 1 24-07-2008 12:07 AM
site responding slow via linux proxy yogeshmalik77 CentOS / RHEL / Fedora 2 15-05-2008 12:48 PM
imap errors / server slow down seed2be Mail Servers 0 06-03-2008 09:36 PM


All times are GMT +5.5. The time now is 12:40 AM.


Powered by vBulletin® Version 3.8.5 - Copyright ©2000 - 2010, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.3.2
©2005-2010 nixCraft. All rights reserved

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38