+:::::: In Passwd File

hi i m new to linux
i recently realise that the /etc/passwd have this line +:::::: at the last line of the /etc/passwd file.

I do not have my NFS and NIS turn on.
But why is there such field present. If i comment out the field will there be any conflict?
Can anyone please guide.

I don't have it. Did you run NIS earlier? It could be a leftover. When you remove it, don't forget to check /etc/shadow for a such a line (and /etc/group?).