Can MX records point to multiple cnames

[Ben Davies]

I want to use oxymail.oxy.com as my mx record for all my external machines.
I also want oxymail to be a cname for each of two firewalls.  Can I do this:

server1.oxy.com.     in     a     1.1.1.1
server1.oxy.com .    in    mx    10  oxymail.oxy.com.

firewall1.oxy.com.    in    a    1.1.1.2
oxymail.oxy.com.    in    cname    firewall1.oxy.com

firewall2.oxy.com.    in    a    1.1.1.3
oxymail.oxy.com.    in    cname    firewall2.oxy.com.


or does the machine reverenced by the cname need to be an "A" record


We get too much mail to just do this and the DNS and BIND book does not
address this clearly.