for intranet application apply user credentials to email server

avoid hard coding and exposing user id's and passwords

<errorMail from="elmah@example.com" to="admin@example.com" subject="..." priority="Low|Normal|High" async="true|false" smtpPort="25" smtpServer="smtp.example.com" useSsl="true|false" userName="johndoe" <-- already signed in to server password="secret" <-- is it possible to use CredentialCache.DefaultNetworkCredentials noYsod="true|false" />