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Old 03-20-2005, 04:36 PM   #1
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Registered: Nov 2003
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Unhappy Extremely Slow DNS Host Resolution

My system suffers from very slow internet performance, and it never used to. I am running a dual boot system with Mandrake Linux 10.1 and is the only Linux machine on my home windows network. Anyway, my linux box used to load web pages at the same speed, if not faster then my windows machines. However, this problem developed literally over night with no apparent reason, one day it was fast, the next it was slow, and I had made no configuration changes at all in that time frame that could cause the problem, infact I wasn't even home. After a series of tests both on my local network and on the internet I believe that my Linux box is having trouble resolving DNS names on the internet. For example I can ping any web site in konsole and it takes between 5 and 7 seconds for a response. However, if I ping the IP address of any web site, ping responds at a normal rate. Also if I type in the url of a web site in any browser it takes somewhere around 20 to 30 seconds to load the page, but if I type in the IP of the same web site in any browser ( it arrives there instantly. I also ran many tests to determine if it could be a problem with the network card, I booted in Windows XP to see if a similar problem occured in that OS and it was just as fast on the internet as my other machines, I streamed video from my linux box to Windows Media Player on my windows box using Samba and it ran perfectly. All this considered I believe it is a problem with the way DNS is set up on my linux box, however I am not absolutly sure and any other theories would be appreiciated. Also, any attempts I have made to alter these DNS settings have failed. If you have any suggestions about how to correct this issue please contact me. If you wish to contact me personally my email is posted in my profile I believe.

My home network consists of 3 Windows XP machines, 1 Xbox, and my Mandrake 10.1 machine. All of these machines are connected to a LinkSys router/switch which is then connected to my D-Link ADSL modem and provides my file sharing capabilities and access to the internet. My Mandrake 10.1 machine is an older HP Athlon Thunderbird system with 512 MB Ram and a ATI Radeon 7200 64MB DDR AGP 4x video card. The network card is built in to the motherboard and is a Realtek 10/100 card. My Mandrake 10.1 system is fully updated, however the apaulingy slow internet performance problem existed before I updated it. Any help would be greatly appreciated. Thank you very much for taking the time to read this.
Old 03-20-2005, 06:22 PM   #2
Registered: Dec 2004
Location: Ohio
Distribution: Fedora Core 3
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I have a similar problem at work with our DNS proxy.

If your linux systems are using dhcp to gather dns they could be instructed to use the router as a dns device which simply proxies the request.

cat /etc/resolv.conf

If the nameserver is the ip address of your router then try this.

host or use nslookup

See if either complains about lookups.

If that seems to be the case, then simply fetch the dns information from your router or provider and manually enter that into /etc/resolv.conf or if your router has options to specify the dns servers in the dhcp server settings update those.
Old 03-20-2005, 06:36 PM   #3
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Registered: Nov 2003
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Thank you for your assistance cylix. My resolv.conf file has the same DNS configuration as my router. There are three IP Adresses listed in my resolv.conf file and they match the ones displayed in my routers configuration. This is very frustrating because there does not seem to be a reason that makes any sense for this problem. If you have any other suggestions it would be a great help. Thanks again.
Old 04-01-2005, 04:19 PM   #4
Registered: Nov 2003
Location: England
Distribution: mandriva 2005 le
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longsword, check out this post:

I just tried it and it did the trick.

Not really sure what it did, but it worked!


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