I know fastmail and gmail can setup the third party sender in their system.
My requirement is, since I am using pobox.com for forwarding, sometime I need to reply this message from a real pobox.com address. Since pobox does provide smtp server, so I want to use this smtp server to reply from pobox.com address from within the third webmail system (b/c pobox basic account doesn't provide webmail).
gmail can setup that, but google is totally blocked in my s*** country.
fastmail can do that too, but I didn't subscribe to FM yet.
Any other providers for suggestion? thanks.