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Simon Williams wrote:
In the last couple of weeks, mail has been intermittently bouncing. What I don't understand is that the bounce messages are from Hostgator. It seems that there is some problem with the MX and so the mail servers are falling back to delivering to the A record. Is it possible that some mail servers are skipping the MX completely?
The standard specifically forbids falling back to A record if MX records exist.
I've seen it happen on a few broken sites (one of than a DNS consultancy ironically) over the years.
Usually points to a weird choice of DNS resolver.
I called 123reg when this first happened and they couldn't see anything wrong. It was working again at that point, so I put it down to someone making a mistake somewhere. Now the problem is back, but it's still random whether it will bounce or deliver.
The delegation of the domain is messy. With the name servers having two sets of names:
ns.123-reg.co.uk
ns2.123-reg.co.uk
ns2.hosteurope.com.
ns.hosteurope.com.
I'd get that fixed if it were my domain. I've seen this before so
probably applies to a large set of 123-reg customers (sigh).
Don't think it should cause any issues, but it increases the complexity involved in DNS resolution to no good effect.
My guess is the sending system is bust if it is emailing the A record. I think "show us a bounce" is the next step to progress this... Simon -- The Mailing List for the Devon & Cornwall LUG http://mailman.dclug.org.uk/listinfo/list FAQ: http://www.dcglug.org.uk/listfaq