When using a Python script to send max sized vlan packets on a BCM4401 nic (driver: b44), the Intel I217-V nic (driver: e1000e) only receives packets with a maximum size of 1514 bytes and reports a length error for the 1518 bytes sized packet.
When sending the packet from the I217-V and receiving with the BCM4401 however, both packets are received without errors. This still happens when both sides are directly connected thru a single ethernet cable. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=212613 hostnamectl | grep "Operating System": Operating System: Debian GNU/Linux 10 (buster) Kernel version I217-V: 5.12.0-rc4 (net-next) Kernel version BCM4401: 4.19.0-181 Python script: from scapy.all import * pkg1 = Ether(dst="FF:FF:FF:FF:FF:FF")/Dot1Q(vlan=100, type=0x8000)/Raw(load=b"\xFF" * 1500) print("1st lenght: " + str(len(pkg1)) + " Byte + 4 Byte FCS") sendp(pkg1, iface="eth0.100") pkg2 = Ether(dst="FF:FF:FF:FF:FF:FF")/Dot1Q(vlan=100, type=0x8000)/Raw(load=b"\xFF" * 1496) print("2nd lenght: " + str(len(pkg2)) + " Byte + 4 Byte FCS") sendp(pkg2, iface="eth0.100")
