How to check dynamic DNS

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#1 Tue, 12/27/2005 - 22:02

How to check dynamic DNS

I have a router ( to which is connected the Fedora box ( Presently all zones files show addresses as Router is set to for its DNS with secondary to the ISP's DNS server.

I have installed the dynamic DNS option on both the router and the fedora box but am not seeing any changes in the zone files or anywhere else.

Hosting works within the LAN so virtual min is doing its job. Names resolve within the LAN.

Am using DYNDNS to link an to my roving IP on the router. All DNS traffic (53) and http (80) traffice and then forwarded to

Domains are then registered to and Once I have the intended application suite operational I will place the server in the ISP's premises.

Any help on what to look for to sort out the dynamic DNS bit will be most appreciated.



Tue, 12/27/2005 - 22:37

Hi Richard,

I'm not sure how much this will help solve your problem, but I'll make two comments regarding your post:

1) Using Dynamic DNS in a hosting environment is a very bad idea, assuming you do not have a static IP address, and especially if you are running your own DNS servers. DNS servers, and hosting servers in general, are expected to be configured with static IP addresses, otherwise your clients/users will have a very unstable system. There are a few things you can do to help here, such as using low TTLs on your DNS entries, but you will still have problems due to DNS caching on hosts that do not respect the TTLs.

2) Make sure when you forward port 53 for DNS that you do so for both TCP and UDP.

Tue, 12/27/2005 - 22:58

Thanks Alan,

Have added port 53 UDP. Checked router and I had left it out.

As for the dynamic ip setup. I only intend to use it for a month or two while I setup an application suite.

That said it is still important to get it running.



Wed, 12/28/2005 - 16:47

An easy way to find out how it is resolving would be to simply hit and use their web based nslookup to find out how it is resolving elsehwere.

Thu, 12/29/2005 - 02:56

Thanks Andrew. Checked and the IP being reported is the machines local address (

I am using ddclient ,

Problem is obviously being too cheap to buy a fixed IP :(
That not withstanding ddclient should be updating the zone files. Or so I thought.

Will post the answer for if I find it.

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