VPN : FreeSwan to Cisco Pix 5.3(1)

[cygnetrower1]

Does anyone have any experience of setting up a VPN between a pix running 5.3(1) and Freeswan on Linux.

the error occurs at phase 2 after the sa has been authenticated on the linux sidethey receive the message
ISAKMP Message has an unknown value: 6

 

[shaodius]

We've got several mandrake machines running freeswan connected to a PIX firewall running 5.1(5). Our configurations are as follows:

PIX side:
access-list 126 permit ip 192.9.200.0 255.255.252.0 192.168.1.0 255.255.255.0
crypto ipsec transform-set myset esp-des esp-sha-hmac
crypto ipsec transform-set myset1 esp-3des esp-md5-hmac
crypto ipsec transform-set myset2 esp-3des esp-sha-hmac
crypto ipsec transform-set myset3 esp-des esp-md5-hmac
isakmp key testtesttesttest address 1.2.3.4 netmask 255.255.255.255
crypto map theMap 24 ipsec-isakmp
crypto map theMap 24 match address 126
crypto map theMap 24 set peer 1.2.3.4
crypto map theMap 24 set transform-set myset1 myset2 myset3 myset

route outside 192.168.1.0 255.255.255.0 9.8.7.6 1

(1.2.3.4 is remote (Linux) outside IP, 9.8.7.6 is local gateway address)

On the mandrake side, we have ipsec.conf with:
conn dadz-workz
left=1.2.3.4
leftsubnet=192.168.1.0/24
leftnexthop=5.6.7.8
right=13.12.11.10
rightsubnet=192.9.200.0/255.255.252.0
rightnexthop=9.8.7.6
authby=secret
pfs=no
auto=add

where 1.2.3.4 is linux outside, 5.6.7.8 is linux gateway, 9.8.7.6 is PIX gateway and 13.12.11.10 is PIX outside address.

We also have the following rules added to the iptables firewall on the linux side:

iptables -A INPUT -s 13.12.11.10 -d 1.2.3.4 -j ACCEPT
iptables -A INPUT -s 192.9.200.0/22 -d 192.168.0.0/24 -j ACCEPT
iptables -A FORWARD -s 192.9.200.0/22 -d 192.168.1.0/24 -j ACCEPT

and modified the MASQUERADE rule to read:

iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -d ! 192.0.0.0/8 -j MASQUERADE

where once again 13.12.11.10 is the PIX outside address and 1.2.3.4 is the linux outside address.

when testing the VPN from the linux machine with a ping, it is necessary to specify the interface, ie.
ping -I 192.168.0.1 192.9.200.10
to ping 192.9.200.10 from the linux machine.

Hope this helps.
Shaodius