Simultaneous IKEv1 and IKEv2 connection support in Strongswan
Solution 1:
Yes, you can do IKEv1 and IKEv2 simultaneously as long as you have both pluto and charon installed and the daemons running. Use this in your config setup:
charonstart=yes
plutostart=yes
And use the keyexchange parameters in your ipsec.conf's conn sections:
conn foo
...
keyexchange=ikev2
...
conn bar
...
keyexchange=ikev1
...