Required Port 443 For Veeam Backup & Replication Is Occupied By Another Application

She considered running Veeam on port 8443 internally, then setting up an IIS ARR (Application Request Routing) reverse proxy on port 443 that forwarded traffic. Elegant in theory. In practice, Veeam’s API hard-codes redirect URLs in its authentication handshake. The moment the proxy forwarded a request, Veeam would generate a callback URL with :8443 , the browser would throw a CORS error, and backup jobs would fail with cryptic "token mismatch" errors.

Secure connections to Veeam Cloud Connect service providers. She considered running Veeam on port 8443 internally,

(Be careful – this removes all HTTPS:443 reservations for non-admins.) The moment the proxy forwarded a request, Veeam

She had been planning this migration for six months. The old tape libraries were being retired. The new all-flash object storage array, affectionately nicknamed "The Vault," was racked and stacked. Veeam Backup & Replication v12.1 was the orchestrator, the brain that would move 4.2 petabytes of financial transaction data from the production cluster to immutable cloud storage. And its control heart—the web UI, the REST API, the service endpoint—needed port 443. The old tape libraries were being retired

No errors. No port conflicts. Throughput: 1.2 GB/s.

The most frequent culprits on Windows Servers are often built-in Microsoft services:

Port 443 is the industry standard for secure web traffic (HTTPS). Veeam Backup & Replication utilizes this port for several essential tasks: