Basic pluto test:

"westnet-eastnet": 192.0.1.0/24===192.1.2.45[@west]...192.1.2.23[@east]===192.0.2.0/24

the policy has been adjusted to permit only serpent for phase 1 and serpent
for phase 2.

serpent is supported with IKEv1 and IKEv2, and for ESP by netkey and klips.
However, NSS does not support serpent, so IKE is not yet supported.