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Troubleshooting performance and slowdown issues caused by IPv4 Large Send Offload

By default, Bitdefender automatically detects the network configurations on your endpoint and creates an appropriate basic firewall profile.

Bitdefender also adds detected networks to the profile as trusted or untrusted network zones, depending on their configuration.

In some cases, you might experience the following issues:

  • Logon failure - unknown user name or bad password.

  • When running a gpresult, you may receive the following message - "INFO: the user does not have RSOP data".

  • When logon the system remotely using RDC, you may receive this message - "Because of an error in data encryption, this session will end".

  • Other endpoints are accessing the endpoint very slow.

  • The download from a network share resource is very slow.

Because this issues might reside at Network Driver Interface Specification level (NDIS), you need to disable the option called "IPv4 large send offload" from your network card, by following the steps below:

  1. Click on Start and select Run.

  2. Write ncpa.cpl.

  3. Once the Network Connections window is opened, right click on your Local Area Network connection, and choose Properties.

  4. Press on Configure and navigate to the Advance tab, once the network card properties is opened.

  5. Disable the option IPv4 large send offload.

  6. Press OK and exit.