[clug] Single MX, multiple A records

[Alex Osborne]

Alex Satrapa wrote:
> On 01/08/2008, at 12:07 , Alex Osborne wrote:
>
>> From what I've seen, DNS servers will usually return multiple A 
>> records in a random order each time they're queried.  
>
> That might work if DNS lookups aren't cached.

Again, just an observation and it may not be configured in this 
particular case but a low time to live can be specified in this sort of 
situation:

% dig www.google.com
[...]
www.google.com.         85366   IN      CNAME   www.l.google.com.
www.l.google.com.       288     IN      A       66.249.89.104
www.l.google.com.       288     IN      A       66.249.89.147
www.l.google.com.       288     IN      A       66.249.89.99

% dig www.cnn.com
[...]
www.cnn.com.            199     IN      A       64.236.24.12
www.cnn.com.            199     IN      A       64.236.29.120
www.cnn.com.            199     IN      A       64.236.91.21
www.cnn.com.            199     IN      A       64.236.91.23
www.cnn.com.            199     IN      A       64.236.16.20
www.cnn.com.            199     IN      A       64.236.16.52

So I guess caching shouldn't be a problem, provided the caches honour 
the TTL properly.