You can simply ignore that alert by CSF firewall, it is given just as a precautionary measure to you. Basically what happens with our site is that when someone browses your site name servers are used to respond and thus in case if ns1.vornahost.com goes down ns2.vornahost.com will also go down as both of them are on the same server. So CSF warns you to locate ns2.vornahost.com physically on another server so that even if one name server ( ns1.vornahost.com ) goes down your site remains online using ns2.vornahost.com that is your second name server on the other server and the downtime of your site is reduced. So we would kindly suggest you to please ignore those alerts.
این جواب پشتیبان کارو بود وقتی ازش اینو پرسیدم.
خلاصش اینه.
بی خیالش بشو . مهم نیست.