Many A-records

[Jeff Lasman]

On Sunday 04 April 2004 12:05 am, fih wrote:

> I was once told that a network interface should have only one
> A-record and a corresponding PTR record. Since you probably know many
> people likes to tweak this and I'm doing my best to fight it.

This was true in the early 1990s.

You can have many A records pointing to the same IP# (and therefore to 
the same network interface).

There seems to be a lot of argument as to what you should use for PTR 
records.  There's nothing to prevent you from serving more than one PTR 
record for the same IP, but if my recollection servers, there's not 
much to be gained by it, since most resolvers don't know how to handle 
multiple PTR records.  We give each machine on hostname (I hope 
everyone does <smile>), and every IP# on that machine (no matter what 
the network interface) get's a PTR record to that hostname.

> While fightning it i also gets alot of questions about why we can't
> have many A-records pointing to the same IP. Does any body know if
> there is a RFC or Best practise DNS documentation that i can refer to
> or am I totally wrong??

You can and often should have multiple A records pointing to the same 
IP#.  For example if you have multiple domains on the same IP# you'd be 
required to, since you can't use a CNAME record to define the IP# 
address for the name of a zone.

> Also if my company likes to sell services based on DNS names and we
> have customers that can't see the external namespace we use for our
> services. They want me to add fake A-records in the customers
> namespace so our services will have different names depending who is
> asking.

I'm sorry, but I don't understand this question well enough to answer; 
hopefully someone else will.

Jeff
-- 
Jeff Lasman, nobaloney.net, P. O. Box 52672, Riverside, CA  92517 US
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