Outbound connect(2) failures are not propagated to guest correctly => Fixed in SVN

[reidpr]

Steps to reproduce (see also notes below):

1. Install a Debian Wheezy 64-bit guest on a Mac OS 10.7 host.
2. Configure a NAT network interface.
3. Install links in the guest.
4. Locate a server which gives a "destination unreachable" error when pinged from the host.
5. Inside the guest, try to use links to access that server: "links ​http://example.com".

Expected behavior:

• links immediately displays a "connection refused" error (i.e., the same as what the host does)

Actual behavior:

• links waits until the connection times out and then displays a timeout error
• netstat shows the connection in SYN-SENT state until timeout

Workaround:

• Packets to the host in question can be rejected inside the guest, e.g. "route add -host x.y.z.w reject".

Notes:

• I hypothesize that the ICMP packet reporting the problem is not being passed to the guest.
• I suspect the precise details of which Linux are installed as the guest aren't important.
• I also suspect the problem can be reproduced with a simple connection refused from a reachable server, e.g. "​http://google.com:9999".
• See also ​https://forums.virtualbox.org/viewtopic.php?f=8&t=48644

Thanks for your hard work on VirtualBox!

[JonC]

I am also seeing this behaviour. ICMP "destination unreachable" packets are dropped between the host and the guest. I have observed it for NAT and host only networks.

In my opinion this is not a problem with the guest network configuration / packet filtering. My host and guest networks are configured in an almost identical manner, the guest shows this problem but the host does not.

• Version: 4.1.16 r78094
• Host type: Linux (RHEL 6.2)
• Guest type: Linux (RHEL 6.2)

I have also observed this behaviour in the below configuration (where clearly the host and guest networks cannot be configured too similarly).

• Version: 4.1.8 r75467
• Host type: Windows 7
• Guest type: Linux (Fedora 16)

[Valery Ushakov]

The fix for reporting connect(2) failures to guest as either TCP RST (connection refused) or ICMP (unreachable) has been committed to 4.3 branch.

Problems with handling of inbound RST for established connections is covered by #11696.

[Frank Mehnert]

Fix is part of VBox 4.3.22.