xn ethernet issues as DOMU under NetBSD DOM0

[Stephen Jones]

Hello, I'm seeing a problem with networking running under FreeBSD 10.3 as a XEN DOMU (HVM) on a NetBSD 7 XEN DOM0 (XEN45).
In searching the list archives, I did see mentions of there being an issue with scatter/gather with symptoms affecting
ssh connections in/out going and likely other network issues.  Are there sysctl parameters or other settings that could get
around this issue?

The ssh symptom (as reported by others) looks like this:

debug1: Local version string SSH-2.0-OpenSSH_6.8 NetBSD_Secure_Shell-20150403
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2 FreeBSD-20160310
debug1: match: OpenSSH_7.2 FreeBSD-20160310 pat OpenSSH* compat 0x04000000
debug1: Remote is NON-HPN aware
debug1: mac 0x0, -1 -1
debug1: SSH2_MSG_KEXINIT sent
Bad packet length 168430090.
debug1: mac 0x0, -1 -1
ssh_dispatch_run_fatal: message authentication code incorrect