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I'm wondering if I need to clear some cache or something with the issue I'm having.

I'm trying to remove A records from a DNS Zone and replacing them with a CName record that has the same host name.

Remove-DnsServerResourceRecord -Zonename $line -InputObject $record -Force
Add-DnsServerResourceRecordCName -Zonename $line -Name $hostname -TimeToLive $ttl -HostNameAlias $target

This throws me:

Add-DnsServerResourceRecordCName : Failed to create resource record @ in zone zone.tld on server NS01. At C:\admin\updatettl.ps1:56 char:4 + Add-DnsServerResourceRecordCName -Zonename $line -Name $hostname > -TimeToLive ... + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : ResourceExists: (@:root/Microsoft/...urceRecordCName) > [Add-DnsServerResourceRecordCName] , CimException + FullyQualifiedErrorId : WIN32 9709,Add-DnsServerResourceRecordCName

Any ideas? Thanks

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1 Answer 1

up vote 10 down vote accepted

Microsofts DNS Server implementation will not allow you to create a CNAME at the zone apex as per RFC 1034 §3.6.2.

The error you receive (9709, DNS_ERROR_CNAME_COLLISION) is a bit cryptic, but you won't (and shouldn't) be able to add it anyways.

On the other hand, placing a CNAME RR at the apex effectively introduces a collision with the NS and SOA records for the zone, at which point the error does make some sense

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Seems that is correct. When I try to create a CName on @ it throws me this error but when the hostname is set to something like "www" it has no problems with this. Thanks! – Elfar Alfreðsson Jul 31 '14 at 18:31

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