Network problems could be detected by enabling packet logging at the guest side or at the host side, but using the built-in capability of VirtualBox to create pcap files might provide even more useful information because it contains a log of really all packets received and sent by guest.
To enable network tracing do the following:
# VBoxManage modifyvm [your-vm] --nictrace[adapter-number] on --nictracefile[adapter-number] file.pcap # VirtualBox -startvm [your-vm]
# VBoxManage modifyvm "ubuntu" --nictrace1 on --nictracefile1 file.pcap # VirtualBox -startvm "ubuntu"
Note: Don't forget to disable tracing after you finished the investigation because your hard disk will quickly be filled by pcap files in case of intensive network usage.The port-forwarding configuration might be affected by this setting as well (this is valid for releases prior VirtualBox 4.0).
Note: If the situation is 100% reproducible and it takes some time to reproduce, the following steps are recommended to create the pcap file:
- Prepare the environment to test, "lead" your application very close to the state when the problem appears.
- Press host-S (take a snapshot).
- Press host-Q, select shutdown with discard to snapshot.
- Run the VM again and finish the test.