Npcap 1.81 introduced the ability to inject packets with 802.1q VLAN headers in order to communicate VLAN information to the miniport driver that sends the packet. The 4-byte VLAN header is removed and converted to NDIS-internal metadata before sending to the lower driver, which adds the header back if needed before putting it on the physical medium. The miniport communicates the maximum frame size to Npcap as the maximum size without the VLAN header, but Npcap 1.81 was interpreting it as the maximum size with the header, so it was incorrectly rejecting packets that would be equal to the maximum size when the header was removed.
This issue was resolved in b3a9703
Npcap 1.81 introduced the ability to inject packets with 802.1q VLAN headers in order to communicate VLAN information to the miniport driver that sends the packet. The 4-byte VLAN header is removed and converted to NDIS-internal metadata before sending to the lower driver, which adds the header back if needed before putting it on the physical medium. The miniport communicates the maximum frame size to Npcap as the maximum size without the VLAN header, but Npcap 1.81 was interpreting it as the maximum size with the header, so it was incorrectly rejecting packets that would be equal to the maximum size when the header was removed.
This issue was resolved in b3a9703