I have a site-to-site vpn tunnel between two PIX Firewalls.
Is possible to build on one side another site-to-site vpn tunnel with the third PIX ?
You can only use one crypto map on an interface but you can have sequence numbers within your crypto map so from your config
The existing tunnel
crypto map mykink1 1 ipsec-isakmp
crypto map mykink1 1 match address 101
crypto map mykink1 1 set peer 188.8.131.52
crypto map mykink1 1 set transform-set aesonly
Your new tunnel
crypto map mykink1 2 ipsec-isakmp
crypto map mykink1 2 match address "acl number"
crypto map mykink1 2 set peer "new peer address"
crypto map mykink1 2 set transform-set "new transform set"
crypto map mykink1 2 set security association lifetime seconds "number of seconds"
You need to fill in the right values within the "" marks.
Note the sequence number has incremented from 1 in your first entry to 2 in the second entry.
You can specify the security association lifetime within the crypto map config which overrides the global settings.
Adding this config should not affect your existing tunnel.