Your right the log shows the domain that user is from, that is his ISP at home.
Feb 25 00:21:21 ws1 ipop3d[20944]: Login user=b_user host=ispaccount.isp.com [123.123.123.123] nmsgs=23/23
I have edited the above log entry for privacy.
That is not a sendmail log entry, it is an ipop3d log entry.
In order to see why the genericstable is not transforming the address the way you want it to, we have to know what the address looks like to start with. What are the user's mail settings in Outlook, i.e. what has s/he defined their email address to be? Whatever it is, that should be what turns up in their From: header unless you have a genericstable entry for that domain and that domain is in the generics-domains file.
Paul.
