Virtual Networking issue

Discussions about using Linux guests in VirtualBox.
Post Reply
PowaUza
Posts: 1
Joined: 15. Nov 2022, 05:29

Virtual Networking issue

Post by PowaUza »

I have a test lab, where I have a virtual router running in virtualbox.
The guest / firewall, is a bare bones debian 11 system, using DNSMasq/IP Forwarding, IPv4 only on all interfaces everywhere.
Host is mint 20.1.
NIC in host is RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller.

The host has a cellular modem, the WAN side of the VM is NAT, sharing that 5G modem with the host.

The LAN side is bridged to the physical NIC on the hosts LAN.
So that NIC serves both access to the host on its own IP, and bridge to the firewall through virtualbox.

This has been working extremely well, and as far as ATT knows, my whole home internet is a galaxy S7 on an unlimited data plan.

However now three times it has gotten into a strange state. (over 7 months, running 24/7)
*some* LAN clients start experiencing a huge bottleneck to the internet.
They can get through the firewall, but at speeds that are like 500kbs/50Mbps (The connection is throttled to 50/50 )
Other LAN clients using the same virtual firewall (and host) are unaffected, once affected a LAN client stays affected seemingly indefinitely, so it is not transient, it is permanent for that client when it happens.
Most at one time three clients affected 4 functioning at the same time.

Rebooting the guest does not alleviate, restarting virtualbox service does not alleviate, rebooting the host does.

I can have to computers side by side taking the same pat through the virtual router, one works fine, the other has the ingress choke.

While in that state, and since rebooting the host does not seem to affect anything I have tried every network adapter type presented, and it has no effect.
Only rebooting the host.

When in this state affected client can iperf to router and get expected speeds, and the router can do an ookla terminal speed test and get appropriate speeds,
So it is essentially *some* clients getting *through* the router.

I attached all logs for that vm, one occurrence was today, problem for one LAN client had been persistent over a week, host was rebooted today, resolved issues.

I am not even 100 percent certain it is virtualbox, it is just the one point the affected and unaffected have in common.
So if you have experience in the homebrew routing side, please feel free to throw me a bone.

So aside from logs, what else can I possibly check or gather for further diagnosis if/when it happens again?
Attachments
Logs.tar.gz
(121.31 KiB) Downloaded 4 times
Post Reply