Remote file copy over VPN stalls at exact file size threshold

Scenario

Large files fail over VPN at a repeatable size while small transfers work.

Recommended Resolution Path

1. Check MTU, fragmentation, and any gateway file inspection limits.
2. Compare SMB behavior with another protocol to narrow the path issue.
3. Test from another user or another tunnel profile if available.
4. If one threshold keeps appearing, capture packet traces before changing multiple settings at once.

Technician Notes

Confirm the result, document the root cause, and record any preventative action worth standardizing.