On 27 Sep 2006 at 11:54, John Lyon wrote:

> 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 _is_ a silly anti-spam measure, but one that many sites are 
taking, not just physics.org (not sure what point anyone sees in it). 
So we now recommend just adding an MX record for the LISTSERV server. 
It shouldn't be needed, but it doesn't hurt either.

-- 
Francoise Becker

There is only one LISTSERV(R) -- the product that launched the 
email list communication industry in 1986. To discover the 
story behind LISTSERV, visit:
http://www.lsoft.com/corporate/20anniversary.asp