Colocation to Virtualization

There are 2 IPs assigned to each of the NetApp units here.  One for the regular network VLAN and one on the ISCSI network.  When querying the DNS for the IP information, both IPs would come back. Turns out that under options in the NetApp command line, dns.update.enable was the issue.  This option told the NetApp to send DNS updates to the DNS servers, thus auto updating the records with both its public IP and ISCSI VLAN IP.  This was causing an intermittent problem for all servers and clients that were trying to access NFS or CIFS (windows) shares on the NetApp.

Incorrect DNS information
$ nslookup netapphn

Name:    netapphn.x.com
Address: 127.x.1.85
Name:    netapphn.x.com
Address: 127.x.200.85

Our other NetApp off site was not having this issue.  It only resolved to one IP

From the Netapp CLI, it shows that DNS updating is turned on
NAS> options dns.update.enable
dns.update.enable            on

Trun it off
NAS> options dns.update.enable off

Now, verify that the change took
NAS> options dns.update.enable
dns.update.enable            off

The change did take.  Now time to check the DNS
$ nslookup netapphn
Name:    netapphn.x.com
Address: 127.x.1.85

Great, DNS now resolves correctly.  No more hading out two IPs.

Note:  Will need to flush the DNS cache on the server or delete the incorrect “A” record out of the DNS server to see immediate results.

~ by Kevin Goodman on October 23, 2008.

Posted in Miscellaneous, NAS, Networking
Tags: active directory, DNS, dns.update.enable, duplicate netapp ip, LinkedIn, na dns, netapp, NetApp Active Directory, netapp dns, netapp ip, netapp options, option dns.update.enable