dns server and client load blancing behavior

[Mark_Andrews at isc.org]

> dear all,
> 
> if I has following RR
> ms1    IN    MX    0    ms1_1
>            IN    MX    0    ms1_2
> ms1_1    IN    A    10.10.10.1
>                IN    A    10.10.10.2
>                IN    A    10.10.10.3
> ms1_2    IN    A    10.10.10.4
>                IN    A    10.10.10.5
>                IN    A    10.10.10.6
> 
> then query mx Record for ms1,will name server response all the above RRs for
> client,and the what the RR order?
> How long do Mircrosoft client or any other client will cache the RR?
> 
> thank you for your help,
> eric

	ms_1 and ms_2 are illegal hostnames (underscore is not allowed).

	Yes all the records should be returned.

	MX records in the answer section.  A records in the additional
	section.  Apart from that the order is indeterminent.

	Nameservers should cache the records for however long the TTLs
	are.  Many other clients just leave the caching to the local
	nameserver to perform, none are supposed to cache the answers
	longer that the relevent TTLs.

	I all cases they may be cached for less time than the TTL allow.
	
	Mark
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org