CNAME in MX

[Mate Wierdl]

Can a CNAME in an MX record cause a problem for qmail?  
I mean, our sysadm set up

cs.memphis.edu  preference = 10, mail exchanger = mx.cs.memphis.edu

where mx.cs.memphis.edu is an alias.

If it can, how exactly?

Thx

Mate