Is it legal to telnet to a comp on port 25 and forge an email. Not for crime or threats or anything just for fun with people u know. Also, would u get in trouble if u were to to do this by telnetting to a site like optonline.net?

it could be illegal depending on contry of origin and destination.

Just pretend it's illegal and go from there

the worst that probably would happen is if the person or persons receiving the forged e-mail(s) ,complained to their isp's about it. or the persons e-mail account that you forged the e-mail from,when they get a copy of the e-mail they supposedly sent. then you could get a warning or even arrested, depending on where you are. in the u.s.a. you could easily be arrested, and have your account suspended or terminated by your isp. if no complaints are received,most likely - nothing much would happen. with some of the new internet laws i think i wouldn't try it, they're looking to make examples of people hacking into anything these days.

ok, thanks

"Is it legal to [go onto an individual's computer without permission] and [do anything]." Yes, but it is very difficult to get the authorities to go after you. In fact, without serious damages or publicity, most likely nothing will happen.