[cobalt-users] Domain sending e-mail to another domains user:

[<cobalt@xxxxxxxxxxxxx>]

Today I was investigating an issue where domaina.com was getting e-mail
sent to a domainb.com address.
I went into /etc/mail/aliases to investigate for a corrupted file or
something else going wronge I noted:

domainacom:    sales

And futher on in the file

sales:  "|/usr/local/sbin/vacation.pl /var/vacation/sales.msg
sales@xxxxxxxxxxxxxxx", \sales

I checked the domainacom settings, and it turns out that the client had
indeed placed only "sales" into the "Forward E-mail To:" box.  Shouldn't
the cobalt machine be doing a security check for errors like this?
Seems preety simple to me:  "If ForwardTo w/o @ then check USERNAME is
in this domain, if not error/warn".

Anyone else encountered this problem before when handling webhosting?

DC