Multi-Homed address sorting

[Kevin Darcy]

Michael Wilkinson wrote:

> Hey All-
>
> This is a follow up to a thread where a request to reintroduce shared network address sorting in V8 was made.
>
> Mr.Vixie replied saying that he would reintroduce this into 8.2 (if he was able
> to find the patch).
>
> Compiled and tried it last night and got round-robin (almost looked random).
>
> Anybody know if this was made available in 8.2.2. SP5? Paul? Help!!!

What exactly are you looking for? BIND won't *automatically* sort answers by network. The default ordering
scheme for BIND is what I would call "rotational-order-with-random-origin", although it's referred to as simply
"cyclic" in the documentation and code. If you have a small number of records in the RRset, this ordering scheme
results in answers which seem to be ordered randomly (in fact, for an RRset of only 2 records, there is no
difference between so-called "cyclic" ordering and "random").

If you want to override the ordering based on the IP address of the requesting client, you need to use the
"sortlist" option. Make sure you configure the sortlists on *all* of the authoritative servers, though, and
unless you control every server which may answer the name from cache, you'll have to resort to the ugly
pseudo-solution of reducing TTL values to defeat caching.


- Kevin