[strongSwan] IKEv2 PFS disabled

[Alexis Salinas]

I'm answering this request with copy to the list in case some else wants the configuration. As I said before, notice that PFS has to be disabled on StrongSwan for this to work.
Cheers,
Alexis.


Strongswan: 
config setup
        cachecrls=no
        charonstart=yes
        crlcheckinterval=0
        plutostart=no
        strictcrlpolicy=no
        nat_traversal=yes
        plutodebug=none
        charondebug="dmn 0, mgr 0, ike 2, chd 0, job 0, cfg 3, knl 2, net 2, enc 0, lib 0"

conn to-fortigate4.0
        left=192.168.3.47
        leftid=@H020109D0206
        leftsubnet=172.22.0.0/24
        leftnexthop=192.168.2.128
        leftfirewall=yes
        right=XX.XX.XX.95
        rightsubnet=10.0.0.0/24
        ike=aes128-md5-modp1536!
        esp=aes128-md5!
        keyexchange=ikev2
        mobike=no
        ikelifetime=60m
        keylife=20m
        compress=no
        authby=secret
        dpdaction=restart
        dpddelay=10
        dpdtimeout=30
        auto=add
        keyingtries=1
        rekeymargin=3m
        forceencaps=no
        reauth=yes

		
Fortigate:
config vpn ipsec phase1-interface
    edit "omg-p1"
        set type dynamic
        set interface "wan1"
        set ike-version 2
        set proposal aes128-md5
        set psksecret ENC wYvCBAv7cFED5aApm22Ps1hhGZr5pZ4gnAYth7T+a7bN6TVrX9qlZR6gzP6T8JyOQ7zzHZGZR5biQJoHDU4Kz172t5AO0xyVr5zX88g57PwQv+BM
    next
end
config vpn ipsec phase2-interface
    edit "omg-p2"
        set phase1name "omg-p1"
        set proposal aes128-md5
        set replay disable
        set dst-subnet 172.22.0.0 255.255.255.0
        set src-subnet 10.0.0.0 255.255.255.0
    next
end

config firewall policy
    edit 1
        set srcintf "internal"
        set dstintf "wan1"
            set srcaddr "all"             
            set dstaddr "all"             
        set action accept
        set schedule "always"
            set service "ANY"             
        set nat enable
    next
    edit 2
        set srcintf "internal"
        set dstintf "omg-p1"
            set srcaddr "all"             
            set dstaddr "all"             
        set action accept
        set schedule "always"
            set service "ANY"             
    next
    edit 3
        set srcintf "omg-p1"
        set dstintf "internal"
            set srcaddr "all"             
            set dstaddr "all"             
        set action accept
        set schedule "always"
            set service "ANY"             
    next
end



Cheers,
Alexis

-----Original Message-----
From: Nicole Hähnel [mailto:ml at nicole-haehnel.de] 
Sent: 28-Feb-11 06:21
To: Alexis Salinas
Subject: Re: [strongSwan] IKEv2 PFS disabled

Hi,

we are also trying to connect a FortiGate 50B to our strongswan gateway 
with ikev2.
But we are not able to bring the tunnel up until now.

Can you please provide us your FortiGate vpn and firewall configs?

Thanks in advance!

Nicole


Am 13.12.2010 19:04, schrieb Alexis Salinas:
> Thank you both very much for your quick answer, I'll certainly report this to Fortinet as I already have a ticket open with them. And if you think it could be of any help, I can report back when they fix the bug. Just to confirm, by disabling PFS on the Fortigate, everything works.
>
> Thank you,
> Alexis
>
>
>
> -----Original Message-----
> From: Martin Willi [mailto:martin at strongswan.org]
> Sent: December-13-10 12:52 AM
> To: Alexis Salinas
> Cc: users at lists.strongswan.org
> Subject: Re: [strongSwan] IKEv2 PFS disabled
>
> Hi Alexis,
>
>>          esp=aes128-md5-modp1536!
>>          pfs=yes
> The pfs keyword is not used for IKEv2 connections. If the esp proposal
> contains a DH group, a DH exchange is done for CREATE_CHILD_SA
> exchanges.
>
>> ike 0:omg-p1:64:omg-p2:962: incoming proposal:
>> ike 0:omg-p1:64:omg-p2:962: proposal id = 1:
>> ike 0:omg-p1:64:omg-p2:962:   protocol = ESP:
>> ike 0:omg-p1:64:omg-p2:962:      encapsulation = TUNNEL
>> ike 0:omg-p1:64:omg-p2:962:         type=ENCR, val=AES_CBC (key_len = 128)
>> ike 0:omg-p1:64:omg-p2:962:         type=INTEGR, val=MD5
>> ike 0:omg-p1:64:omg-p2:962:         PFS is disabled
>> ike 0:omg-p1:64:omg-p2:962: my proposal:
>> ike 0:omg-p1:64:omg-p2:962: proposal id = 1:
>> ike 0:omg-p1:64:omg-p2:962:   protocol = ESP:
>> ike 0:omg-p1:64:omg-p2:962:      encapsulation = TUNNEL
>> ike 0:omg-p1:64:omg-p2:962:         type=ENCR, val=AES_CBC (key_len = 128)
>> ike 0:omg-p1:64:omg-p2:962:         type=INTEGR, val=MD5
>> ike 0:omg-p1:64:omg-p2:962:         type=DH_GROUP, val=1536
>> ike 0:omg-p1:64:omg-p2:962: lifetime=1800
>> ike 0:omg-p1:64:omg-p2:962: no proposal chosen
> Fortigate expects a DH group in the piggy-packed CHILD_SA creation in
> IKE_AUTH. This seems wrong to me. As we have done a DH exchange in
> IKE_SA_INIT, it does not make much sense to repeat one in IKE_AUTH.
>
> End of section 1.2 RFC5996 says:
>
>> Note that IKE_AUTH messages do not contain KEi/KEr or Ni/Nr payloads.
>> Thus, the SA payloads in the IKE_AUTH exchange cannot contain
>> Transform Type 4 (Diffie-Hellman group) with any value other than
>> NONE.  Implementations SHOULD omit the whole transform substructure
>> instead of sending value NONE.
> You probably should report this bug to Fortigate and/or try it without
> PFS enabled.
>
> Regards
> Martin
>
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