Changes between Initial Version and Version 1 of Ticket #15303
- Timestamp:
- Apr 12, 2016 12:59:54 AM (8 years ago)
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Ticket #15303 – Description
initial v1 1 1 When using a NAT network, the host adapter will generate TCP RST packets in response to packets that are not destined for that interface. For example, here we have the following network setup: 2 2 {{{ 3 3 52:54:00:12:35:02 10.0.2.2 VirtualBox router 4 4 08:00:27:7c:00:6c 10.0.2.15 VM 5 5 }}} 6 6 And the VM sends this packet: 7 7 {{{ 8 8 TCP SYN 9 9 Src: Eth 08:00:27:7c:00:6c / IP 10.0.2.15 / TCP 15717 10 10 Dst: Eth 08:00:27:7c:00:6d / IP 10.0.2.100 / TCP 80 11 11 }}} 12 12 Then, the VM will receive this spurious packet: 13 13 {{{ 14 14 TCP RST,ACK 15 15 Src: Eth 52:54:00:12:35:02 / IP 10.0.2.100 / TCP 80 16 16 Dst: Eth 08:00:27:7c:00:6c / IP 10.0.2.15 / TCP 15717 17 17 }}} 18 18 Note the soruce MAC. This is the host adapter's MAC. The expected result is that no packet will be sent in response to the original packet above, since the target host does not exist on the network and any other host receiving the packet should disregard it since the destination MAC does not match their MAC. 19 19 20 20 I have attached a pcap of the problem that was generated like this (nping is part of nmap): 21 21 {{{ 22 22 arping -I enp0s3 -c 1 10.0.2.2 23 23 nping --tcp --dest-mac 08:00:27:7c:00:6d 10.0.2.100 24 24 }}} 25 25 Tested with VirtualBox 4.3.36, 5.0.12 and 5.0.16 using Debian, Ubuntu and FreeBSD.

