Is that really a relevant question? A full-stack title usually means web front-end, mobile, web back-end (or API), and database. Its a generalist title. You work mostly with HTTP, but even then an API framework may hide that.
If you're deploying to a PaaS you may never care about or notice lower layers. If not, your team may have a specialist (DevOps, platform engineer, network engineer) who manages network configuration, DNS, load balancer, connection pooling, firewalls, VPN, and other details.
If you're deploying to a PaaS you may never care about or notice lower layers. If not, your team may have a specialist (DevOps, platform engineer, network engineer) who manages network configuration, DNS, load balancer, connection pooling, firewalls, VPN, and other details.