We have blocked the ability to forward e-mail to AOL, Yahoo and Comcast e-mail accounts.
We do not allow the forwarding of e-mail to AOL, Yahoo or Comcast because any spam that winds up in your account, and then forwards to any of these ISP's (Internet Service Providers) counts as a blackmark against BANG! Web Site Design (even though we didn't send it, we were the last to touch it).
In the past ALL e-mail from our servers to these ISP's has been blocked which would not allow you to forward, but additionally even legitimate messages to those ISP's subscribers would fail.
We've taken the stance that it's not worth the risk of losing all access for the few clients of ours who wish to forward their e-mail.