A little bit OT: an interesting POP

As I recall from foggy (possibly inaccurate) memory.... PPP supports "plain text" login before PPP is initiated, and also supports logging in after PPP begins "in stream". To be more precise, I recall that years ago our POPS gave login prompts. Some users client software would just start PPP immediately and authenticate in protocol, and others would actually send a typical login sequence and then start PPP. As another scenario, I also seem to recall that some of our access systems prented a logon prompt and the user entered their userid and password, they would get a protocol prompt and would be able to type in the desired protocol (slip, ppp, shell, etc.) and then ppp negotiation would begin (depending on their selection). Hence, I suspect your logon prompt is nothing unusual at all.