ISPs provide on-ramps for Internet connectivity and make money carrying traffic across their network and connecting their network to other internet networks. ISP sales teams typically lead offers with connection and transport services and then follow initial offers with other ancillary, non-billable services. However, these services (like DNS) are often not within an ISP’s core competency.
Managed services like DNS are different from network engineering. While network services require their own expertise with routers and switching, this rarely translates to expertise in DNS.