CDO - and remote SMTP server

[avivit]

1. I wonder, why do I need to add the following lines when sending forms through mail, using CDO component?
2. If I remove these lines and the form is still submitted as it should, and I get the mail as a result as it should, does it mean I do not need these lines?
3. In other words - How do I know if an SMTP service is installed on the local server, and not in another network (besides asking the admin)?

Thanks
*********The questionable code**************
objEmail.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/sendusing") = 2
objEmail.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/smtpserver") = "md.huji.ac.il"
objEmail.Configuration.Fields.Item _
("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = 25

objEmail.Configuration.Fields.Update()
*****************End***************