HTTP not working for ip adresses ending with .2 => fixed in SVN/next 7.0.x maintenance

[Nestom]

How I reproduce this bug :

1. Download Ubuntu cloud image from ​https://cloud-images.ubuntu.com/jammy/current/jammy-server-cloudimg-amd64.ova

2. Import and run the VM using ​this to add a password for root. NAT networking.

3. Start the VM and try

   dhclient enp0s3
   wget 1.1.1.2
   

Result : Timeout (1.1.1.1 an other IPs work fine) an other IP ending with .2 fails.

I found this bug using Vagrant which is easier to use in order to reproduce this bug.

Discussed on the forum before : ​https://forums.virtualbox.org/viewtopic.php?f=7&t=108212&p=530016

[Nestom]

VBox.log

[fth0]

FWIW, I could easily reproduce the issue, which indicates that it does not depend on some special property of your setup.

I created a VM in VirtualBox 7.0.6 clicking through the wizard and booted it with a "randomly" selected Linux ISO. Executing "wget 1.1.1.1" over the NAT adapter worked as expected. When executing "wget 1.1.1.2", the TCP-SYN packets didn't reach a Wireshark capture on the host OS, but could be captured in VirtualBox's "nictrace".

[fth0]

A comparison of the VirtualBox slirp source code between 6.1.42 and 7.0.6 revealed the responsible change, which was introduced with Changeset 92093: In the ICMP and UDP implementations, the macro CTL_CHECK is used, which compares both the host and network parts of the IPv4 address. In the TCP implementation, only the host part gets compared, which is the ".2" in this case.

[aeichner]

Sorry for taking so long to fix this, and thanks fth0 for the analysis. Will be fixed in the next 7.0.x maintenance release.

[galitsyn]

Hi guys,

We just released a new version of VirtualBox today. This issue should be fixed there. Closing it. Please leave a comment if it is still actual for you. As usual, builds are available on Downloads page. Thank you for reporting.

[fth0]

Successfully verified with VirtualBox 7.0.12.