MTU detection and restoration
Open Network diagnostics → MTU detection. MTU is an interface's packet-size limit. This tool tests the path from one selected adapter to one IPv4 target, not bandwidth, and does not guarantee a speed improvement.
Before testing
Stop the HypoMux network service. Select a physical adapter with IPv4 and a target that answers ICMP. Keep the adapter configuration and network stable. VPNs, routing changes, and ICMP filtering can affect results.
Test without changing settings
- Choose the adapter and inspect Current MTU. Refresh its value if needed.
- Enter a target IPv4 address, not a URL or hostname. It must answer ICMP.
- Select Detect recommended MTU. Probing and verification can take about 50 seconds and can be cancelled.
- Read the recommendation. Testing does not apply it automatically.
| Result | Action |
|---|---|
| Current MTU passed; no change needed | Keep it. Values above the current interface MTU were not tested |
| A smaller value is recommended | Verify this is the path being diagnosed before applying; do not copy it to other adapters |
| Timeout, filtering, cancellation, or no result | Check the target and path, then retest; failure is not evidence to reduce MTU |
| Expired result or changed configuration | Obtain a fresh result |
Apply and restore
Apply recommendation shows the adapter and old/new values before administrator Core changes and verifies the setting. Connections may briefly drop; avoid active remote sessions, meetings, and important downloads.
The original value is saved before modification. If needed, stop the network service and choose Restore original for the same adapter. Restoration records remain available after reopening the app. Results older than five minutes or changed adapter identity, source address, or MTU require a new test.
This version modifies the selected interface's active IPv4 configuration, not IPv6 or persistent system configuration. Rebooting returns to system configuration. If applying fails, refresh the current value and preserve the error instead of repeatedly applying blindly.
How the diagnostics differ
- Link health: bound-egress reachability, latency, jitter, and loss.
- NAT type: IPv4 UDP mapping and filtering.
- MTU: packet size on one path, not NAT type or an optimum for every website.
See network checks, NAT, and troubleshooting.