[pkaeding]

You would still be able to use the telnet client to connect to an SMTP server on TCP port 25, just not port 23, right? I don't think that part changed here.

[ajross]

It's... not super clear from the article whether this is a port block or a stateful protocol thing. But yes, you're probably right and SMTP spoofing is probably safe for now.

[Balinares]

I read it as a clear port 23 block.