dynamic DNS updates via DHCP server?

Unanswered Question
Jun 14th, 2008

I have a 2801 router which I am using both for NAT/PAT & DHCP. I have searched unsuccessfully for information on what is required to forward lease assignments to a local DNS server to implement dynamic DNS.

Any information you can share would be greatly appreciated.

I have this problem too.
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bwilmoth Thu, 06/19/2008 - 06:04

The DHCP server sends the update information to the DNM server, not the primary DNS server. The primary DNS

server retrieves this information from DNM via a zone transfer.

The DHCP server will keep an open connection between it and the DNM server so if that connection is not up the DHCP server will attempt to re-connect. If gives up after (I believe) 4 unsuccessful attempts. So if DNM is not accessible the DNS update info never gets sent.

The support for forwarding dynamic updates to DNS like a windows based DHCP server does not depend

on the IOS. You only need to use the following commands:

Router#config t

router(config)#int e0 (or the interface you are using)

#ip helper-address (here you have to place the address of the

external DCHP, the router must be able to ping this address)

#ip directed-broadcast


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