ID Role

mskh

Are columns with an ID role used for training phase? if yes, can i consider the combination of two attributes as an ID role? my dataset has 3 columns, username, ip address, and connection count.

Telcontar120

All special attributes (including id) are not included as predictors in modeling.
You can't have more than one attribute with the role of id in the dataset at one time---if you try to do this, it will "unset" the prior id.  So the only way to have multiple id columns is to give the additional id columns custom special role names (which you can always do) such as id2 and id3.