25 Feb
2026
25 Feb
'26
11:35 p.m.
Hi, I'm investigating migrating Google-internal uses of qemu's slirp-based networking to passt. One major gap I've discovered is the apparent lack of support in passt for something like the "guestfwd" flag the slirp network backend handles: https://www.qemu.org/docs/master/system/invocation.html This allows us to open outbound connections from the VM to an external service listening on a known port. As far as I can tell, passt's tcp-ports and udp-ports flags appear to map to slirp's hostfwd flags, only allowing traffic to flow into the VM. Am I missing something? If this functionality indeed isn't supported, are there plans to add it? Thanks, Peter Foley