> Wondered if anyone could help with a query I have.
>  
> Over the last few days subscribers using the physics.org domain have been automatically deleted from all of my lists. I have checked my subscribers lists and there is no one left with a physics.org address (there were about 20 on each list). Below is a sample from one of the daily monitoring reports I received: 
>  
> 1 09/26 09/26 [log in to unmask]
>                 Last error: 5.2.0 550 5.2.0 Your domain does not have any MX
>                             records.

What I believe the problem is the mailer at PHYSICS.ORG is 
complaining the sending domain does not have an MX record.
If this is the case, then the mailer/domain which is sending LISTSERV 
mail does not have an MX.

Having an MX is NOT required however. An MX is only used if present. 
If not, then the A recorded is used. It's generally recommended not 
using an MX record unless it is different than the A Record. This is 
apparently some silly anti-spam measure that  PHYSICS.ORG is using.

So, the problem is at PHYSICS.ORG with their anti-spam measure. You 
can choose to go ahead and add an MX record to fix this if you want.

It *may* also be they are complaining that you have no rDNS, although 
the text of the error doesn't indicate that.  So check to be sure you 
have a PTR Record (reverse DNS), then deal with the MX problem as you 
see fit.


> All of the deleted addresses report the same error. I have contacted the Email Administrator who says there are no problems with the domain. 
>  
> Has anyone come across a similar problem before?
>  
> Thanks
> Ingrid
>  
>  
>  
> Ingrid Walker
> Institute of Physics
> 76 Portland Place
> London
> W1B 1NT
> Email: [log in to unmask]
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