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Re: multi-levels MX

> Hello,
> One of my users complained about not able to sent to a particular host.
> I checked around and found something interesting.
> Let's say my user was trying to send to  joe@host1.domain1
> Using nslookup, I found out there is no DNS A record for host1.domain1.
> There is however a DNS MX record pointing to host2.domain2.
> Again using nslookup, I found there is no DNS A record for host2.domain2 too !
> There is however a DNS MX record (of host2.domain2) pointing to
> host3.domain3.
> Question 1: Is the set up for host1.domain1 valid ?

  No,  anything at which CNAME or MX points must have valid A.
I recall that even MX pointing to a CNAME pointing to an A is
considered to be break of rules.

> Question 2: If not, then should zmailer (or any MTA) complain ?

  Possibly, altough many have opted to recurse resolution...
(I have attempted such a patch locally..)

> Erone Quek (Postmaster@hydro.on.ca)
> Network Computing Services
> Telecom Division
> Ontario Hydro
> EMail: Erone.Quek@hydro.on.ca

	/Matti Aarnio <mea@utu.fi>