On Wednesday, April 21, 2004, 1:29:27 AM, Scott Truman wrote:
I'm happy with either method obviously. Excuse my ignorance with regards to DNS lookups, but do all the A records come down with the first DNS lookup, or are they fetched each time from the remote server? What are the traffic overheads with incorporating either type of method - I would have thought that the bit mask method would cause less traffic - also with smaller zone transfers?
Hi Scott, Multiple A records can result from a single query:
% nslookup www.yahoo.com
Name: www.yahoo.akadns.net Addresses: 216.109.117.207, 216.109.118.75, 216.109.118.66, 216.109.118.77 216.109.118.73, 216.109.117.205, 216.109.117.204, 216.109.118.70 Aliases: www.yahoo.com
And they should all come from the locally cached copy of the zone file, so they're fast.
A single bitmasked A record would be smaller but require a little more application CPU to decode. Multiple A records may be faster but they're bulkier. I find the multiple A records more readable. It's one of those classic tradeoffs.
Jeff C.