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Competing DDNS updates on multihomed PC using two different DHCP ranges

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We have the Infoblox configured to register the host in AD DNS (DDNS) when it gives out a lease via DHCP. Sure this isn't needed for domain member Windows machines, but it`s wonderful for non Windows machines. 

 

We've had recuring issues where someone, typically booting off a LInux DVD, gets an IP address via DHCP, and the default host name for those linux DVD's, is LOCALHOST. 

 

The infoblox, dittyfully goes ahead and registers LOCALHOST in DNS (so localhost.domain), and suddenly, an nslookup of localhost suddenly points to that box (most clients are configured to auto-add the dns name to dns queries).

 

Is there a way to configure the infoblox to NOT register certain host names, even while leaving the setting enabled globally?

 

 

Re: Competing DDNS updates on multihomed PC using two different DHCP ranges

[ Edited ]
Adviser
Posts: 63
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You can't really filter which hostname gets registered or not.

 

A simple solution to your issue is to manually create a Host record named "localhost" in the zones where the DDNS is enabled and having its IPv4 address set to 127.0.0.1 and IPv6 address ::1

 

This way, a host trying to register "localhost" will be rejected based on the fact that a static record already exists and you'll keep your wanted behaviour.

 

Hope it helps.

 

PS: On a Linux machine, this should not be an issue since there is "localhost" entry in the /etc/hosts file which, by default, has precedence over DNS for name resolution (gethostbyname(3)). Of course, nslookup is always doing DNS queries, hence your results.

Re: Competing DDNS updates on multihomed PC using two different DHCP ranges

GHorne Community Manager
Community Manager
Posts: 254
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Creating a host record isn't enough, it will still get turned into A/PTR if it receives a DDNS update for the matching FQDN. You need to lock the host by adding additional information that wouldn't be in a DDNS update. E.g. extensible attributes ('reserved, do not update') or a MAC address.

 

Setting BOTH the v4 and v6 address should also lock the record

Re: Competing DDNS updates on multihomed PC using two different DHCP ranges

Adviser
Posts: 63
4666     0

Hi Geoff, 

 

This is why I mentionned setting a v6 address too. Maybe I should have made clear to set them both, indeed :-)

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