﻿id,summary,reporter,owner,description,type,status,component,version,resolution,keywords,cc,guest,host
11871,NAT drops packets bigger than 388 byte towards guest,Lukas Tribus,,"NAT mode does not work for me, because all packets bigger than 388 byte (IP packet length; 368 byte IP payload or 360 byte ICMP payload) are dropped.

The test is as simple as:
{{{
ping google.com -s 360
ping google.com -s 361
}}}

or on Windows guests:
{{{
ping google.com -l 360
ping google.com -l 361
}}}

The former (360 byte ICMP payload) works, while the latter (361 byte ICMP payload) doesn't.


I can reliably reproduce this with both Linux and Windows guests (32 and 64bit), on different hardware. The host always runs Windows Vista or Windows 7, both 64 bit. I did not test different host OS'.

This is with VirtualBox-4.2.12, but I can also reproduce this with the old VirtualBox-3.2.16.

The traffic of the testcase has been captured:[[BR]]
 nictrace.cap::
  via the nictrace feature; it is clear that the answer packets do not reach the guests
 host-dump.cap::
  via Wireshark on the host; all answer packets are seen (frame >= 25)


I have no clue why others don't see this behavior; on all my VirtualBox installations I see exactly this issue, and they are different installations on different hardware with different software.

Bridging mode works perfectly fine on those installations.
",defect,closed,network/NAT,VirtualBox 4.2.12,fixed,mtu,,all,all
