Cisco ASA:

• Lifetime: 86400s
• Encryption: AES256 SHA1 DH5

FreeSWAN:

left=ip of freeswan
right=ip of cisco
authby=secret
leftnexthop=default gw of cisco
auto=start
leftsubnet=subnet of freeswan side
rightsubnet=subnet of cisco side
pfs=no
leftid=ip of freeswan
rightid=ip of cisco
ike=aes256-sha1-modp1536
ikelifetime=86400s
rekeymargin=863s
keylife=86400s
keyingtries=0
compress=no
type=tunnel
esp=aes256-sha1