hi, boggins thanks for the links
As I already said , pppoe is the mode my ISP and I have a user id and password to get the connection speed everything.
But pppoe1 is what i ask about,
I find some drop down address of dlink website, is always enabled, which I do not know, whether I need it or not.
Regarding dns , yes, I know that it is a server service of my ISP.
regarding ddns, though I know, it is a dlink website server website, why it is there and always enabled.
Is it another dns server that is really needed for functioning of the router