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18 Jan 2014
How to disable DNS COP lookup at login

We have Cold Fusion 8 on Linux in the DMZ. Teradata 14 resides in the LAN. Logins from the DMZ (jdbc) are painfully slow. The network admin sees repeated DNS requests when logins are attempted. The DNS server is on the LAN. DNS requests are not allowed through the firewall.
We would like the connection request to use the /etc/hosts COP entries on the Cold Fusion server...without attempting DNS lookups. If the jdbc connection is defined with just an IP address (no COP entries) works fine.
Can we disable the DNS portion of logins when using jdbc?

tomnolan 594 posts Joined 01/08
20 Jan 2014

Yes, you can define the Teradata Database hostname in an /etc/hosts file and the Teradata JDBC Driver will use that.
You should specify the COP=OFF connection parameter so that the Teradata JDBC Driver does not perform COP Discovery.
You can specify multiple IP address for a single hostname. You should list the IP addresses of each of your Teradata Database nodes, and define them all as the same hostname.
(repeat as needed for all your Teradata Database nodes)
The problem with this approach is that no round-robin or load distribution will occur. All connections will go to the first IP address listed, unless that node is down, in which case the second IP address will be used, and so on.
The best solution would be to fix your firewall so that DNS traffic is properly allowed through.

20 Jan 2014

Thanks for the explanation...exactly what we were looking for. 

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