DNS server questions

Special K

Diamond Member
Jun 18, 2000
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I have 2 computers connected to the internet via a DLink DI-524 router. The router is connected to a DSL modem. One computer is a regular desktop, the other is a laptop connected via wireless.

Recently, the internet would suddenly stop working for both PCs. We could not browse the web, or access the router through the http interface. We could not ping websites, although we could ping their IP addresses. If I plugged the PC directly into the modem, it worked fine.

I did some searching and this led me to believe there was a DNS problem. The best solution I could find was to power down the router and modem for 10 seconds, then turn them on again. That solved the problem, but it keeps coming back. Manually resetting the modem and router every hour is annoying, so I started looking for other solutions.

I noticed that there is a place in my routers' web interface to enter static DNS servers. I also noticed that when I do "ipconfig /all" at the command prompt, my dns server is currently listed as the router's IP address. Here are my questions:

1. Are the PCs on my network really using my router as a DNS server right now, or are they still somehow using my ISPs DNS servers, and the ipconfig command only displays the router's IP address as the DNS server because we are behind the router?

2. Would setting a static DNS server fix the problem I described above? If so, what should I set the static DNS server entries to in my router's config page?
 

JackMDS

Elite Member
Super Moderator
Oct 25, 1999
29,484
391
126
If this is true, quote: We could not browse the web, or access the router through the http interface.

The part that says "or access the router through the http interface". Means it is a local network problem and has nothing to do with Internet DNS.
 

Special K

Diamond Member
Jun 18, 2000
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I updated the firmware, and no problems so far. Hopefully that works. Can anyone answer my question #1:

1. Are the PCs on my network really using my router as a DNS server right now, or are they still somehow using my ISPs DNS servers, and the ipconfig command only displays the router's IP address as the DNS server because we are behind the router?

I'm just curious. Is my router really acting as the DNS server for my network? Under what circumstances would you use the entries in the router's config page for static DNS servers?
 

spidey07

No Lifer
Aug 4, 2000
65,469
5
76
Your router is acting as a DNS server/resolver. It will cache entries. Your clients send DNS queries to it and it answers if it has the record, if not it asks your ISPs dns servers.

The static entries in your router are if you want to use DNS servers other than the ones your ISP provides you via DHCP.
 

JackMDS

Elite Member
Super Moderator
Oct 25, 1999
29,484
391
126
Your Router does Not act as a DNS server, it obtains the IP of your ISP's DNS server and provides it when the traffic goes to the Internet.

Most ISPs provides DNS service that is Auto obtained by the Router?s WAN side.

If you do not want to use the ISP service, or you have WAN settings that are not even related to the Internet, you use static DNS IP that points to a specific DNS server.

As an Example, if you set your DNS IP on the WAN side of the Router to 4.2.2.2 your DNS server would Not be the one provided by your ISP, but rather the general DNS server provided by Verizon.

Some Software Firewall s cache the IPs of sites that you visit and act thus as a surrogate DNS source if you return to the same site.
 

skreet

Senior member
Sep 7, 2004
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Some routers run DNS Caching servers, others will relay dns requests on your behalf. Others will just give you the direct IPs of the DNS servers and let you get DNS questions yourself.

I prefer the 3rd type myself, never had good luck with residential quality routers that have dns caching servers built-in.