The AES-GCM cutover was authorised and attempted, NH3 side first. It
cannot be completed: UniFi's manual site-to-site IPsec implements no
AEAD cipher. Eight GCM spellings were rejected with
api.err.InvalidPayload while an otherwise identical body carrying
aes256 returned rc:ok, which isolates the enum rather than the
request as the cause. The accepted set is aes128/aes192/aes256/3des.
Both Anaheim tunnels terminate on UniFi gateways, so this blocks the
ESH tunnel on the same grounds.
Measuring while testing also retires the premise. NH3's uplink is a
1 Gbps link, so Anaheim's 2 Gbps circuit was never the relevant
ceiling, and the tunnel sustains 692 Mbit/s across 8 streams rather
than the ~550 previously recorded from a 4-stream run. Compared with
WireGuard over the same gateway and uplink, the deficit narrows from
2.3x at one stream to 15% at eight, so moving this link onto a
different transport is not worth doing.
The constraint is per-stream, around 245 Mbit/s, with both endpoints
idle under load. Parallelising bulk transfers remains the mitigation
and is worth 2.8x at no cost; NFS nconnect is the equivalent lever
for single-stream mounts such as /mnt/smithy on ana-ml2.
FortiGate phase2 for pfi-ana-nh3 keeps the widened proposal list,
which is inert while the peer offers only CBC and avoids a further
renegotiation. The UDM network object was diffed field-by-field
against its pre-change snapshot and is unchanged.
vh
e41d19f1cb