[BlueOnyx:06847] Relaying Denied error

[Samuel Lentz]

I just migrated one of my boxes from BlueQuartz to BlueOnyx.  This 
morning I am having users saying that they are receiving a relaying 
denied error. This is what is in the maillog:

Mar 31 09:42:24 mailserver sendmail[17375]: p2VDgO5d017375: 
ruleset=check_rcpt, arg1=<to at address.com>, relay=[10.4.2.5], reject=550 
5.7.1 <to at address.com>... Relaying denied. IP name lookup failed [10.4.2.5]

If I am looking at the correctly, I am getting a denied due to a failed 
IP lookup (they are sending from an internal IP.)  Do I need to add 
10.4.2.5 to my hosts file?

Thanks,
Sam L.