Sign up for a new internet?

Sounds silly but does not matter. I have a new internet and sometimes, when I'm surfing, I'm directed to a website where I have to enter my data from the contract, ie password, name etc. It's from Huawei, of which is the modem, but I do not know if I should do that. Is that common that you have to log in then but I have registered on the A1 page?

This is completely normal

Ok thanks ^^ do not like just where my data from, certainly not passwords, code, etc. From the Internet.

Have a problem… Registered, then my password, etc. Created and automatically saved to the PC. Now I come but not with these data, as a user, you can only write in the modem anyway and the password should also be correct.