Yes Blat does need to know the address of an SMTP server to work.
Your best best is to get the local IIS to act as an SMTP relay - the error you are getting is simply an indication of its unwillingness to relay as you have got the configuration incorrect. I am assuming here that you are using Windows 2000 and you have an administrative account (the instructions are similar for XP).
The default configuration of the SMTP service on Windows 2000 SP2 and better is not to relay at all so you are going to have to allow connections and relaying from the localhost only:
- First open internet services manager in the administrative tools menu.
- Expand the local server in the tree view on the left and righ click on "default SMTP virtual server" and select "Properties"
- Select the "Access" tab. Firstly click on the Authentication button and check that "Anonymous access" is checked.
- Back on the access property page click the "Connection control" button". Select the "only the list below" radio button and click the "Add" button, in the "Computer" page that appears check "Group" of computers: put "127.0.0.0" in subnet address and "255.255.255.0" in Subnet mask. Press "Ok". Press "Ok" to leave the connectin dialogue.
- Click the "Relay restrictions" button. In the "Relay restrictions" dialogue check "only the list below" is checked, then press add. In the "Computer" page that appears check "Group" of computers: put "127.0.0.0" in subnet address and "255.255.255.0" in Subnet mask. Press "Ok". Press okay to leave the "Relay restrictions" dialogue. Press OKay to leave the properties page.
- Stop and restart the SMTP service by using the buttons on the right of the toolbar.
Et Voila!
/J\