R4.1 provides-network blocks net traffic on Debian 10

[tasket]

Qubes OS version

R4.1

Affected component(s) or functionality

qubes-template-debian-10 (from testing repo)

Brief summary

When using the Debian 10 template for sys-net or sys-vpn, no network traffic is forwarded downstream.

To Reproduce

Configure sys-net to use debian-10 template.

Expected behavior

VMs connection via sys-net should have net access.

Actual behavior

Traffic does not get through.

Additional context

This also occurs with a sys-vpn VM. For example, if sys-net uses fedora-30 and sys-vpn uses debian-10, then sys-vpn will be able to establish a link to the VPN provider, but downstream VMs will be blocked.

Networking for non-provides-network appVMs appears functional.

Solutions you've tried

Using Fedora for all proxy/net VMs.

Related, non-duplicate issues

[SaswatPadhi]

The debian-10-minimal template from ITL testing repo seems to work fine.

[tasket]

Workaround for me was to enable the Qubes buster-testing repo; subsequent update installed new qubes packages and Debian proxyVMs became operational.