[strongSwan] IKEv2 tunnel establishment, initiator does not repond

Fri Sep 17 20:33:22 CEST 2010

Hello Laurence,

a strongSwan log would really help. The only strange thing
that I see in the wireshark response is

                 Transform ID: ENCR_AES_CBC (12)
                 RESERVED TO IANA (7424): <too big (128 bytes)>

Is this a wrong encoding of the AES key size???

Regards

Andreas

  On 09/17/2010 05:07 PM, Groebl, Laurence (Laurence) wrote:
> Hello,
> I'm setting up an IKEv2 tunnel between a Juniper Gateway and Strongswan
> with IKEv2
> Simple configuration: static IP addresses on both side , pre-shared
> secret, tunnel mode (see strongSwan IPsec configuration file below).
> The initiator (Strongswan) sends the first message and gets an answer,
> but then Strongswan does not answer anymore (see wireshark trace below).
> I noticed in the answer of the Responder there is a Certificate Request,
> even though pre-shared secrets are used, could it be the reason why it
> is not responding?
> Best regards,
> Laurence
> --------------
> Wireshark trace:
> No. Time Source Destination Protocol Info
> 1 0.000000 192.168.30.51 192.168.30.254 ISAKMP IKE_SA_INIT
> Frame 1 (386 bytes on wire, 386 bytes captured)
> Ethernet II, Src: Belkin_d0:77:2c (00:17:3f:d0:77:2c), Dst:
> 80:71:1f:b7:b1:85 (80:71:1f:b7:b1:85)
> Internet Protocol, Src: 192.168.30.51 (192.168.30.51), Dst:
> 192.168.30.254 (192.168.30.254)
> User Datagram Protocol, Src Port: isakmp (500), Dst Port: isakmp (500)
> Source port: isakmp (500)
> Destination port: isakmp (500)
> Length: 352
> Checksum: 0x2d58 [correct]
> Internet Security Association and Key Management Protocol
> Initiator cookie: 593AD8AC6A5DB624
> Responder cookie: 0000000000000000
> Next payload: Security Association (33)
> Version: 2.0
> Exchange type: IKE_SA_INIT (34)
> Flags: 0x08
> Message ID: 0x00000000
> Length: 344
> Security Association payload
> Next payload: Key Exchange (34)
> 0... .... = Not critical
> Payload length: 88
> Proposal payload # 1
> Next payload: Proposal (2)
> 0... .... = Not critical
> Payload length: 44
> Proposal number: 1
> Protocol ID: ISAKMP (1)
> SPI Size: 0
> Proposal transforms: 4
> Transform payload
> Next payload: Transform (3)
> 0... .... = Not critical
> Payload length: 12
> Transform type: Encryption Algorithm (ENCR) (1)
> Transform ID: ENCR_AES_CBC (12)
> Key Length (in bits) (14): Key-Length (128)
> Transform payload
> Next payload: Transform (3)
> 0... .... = Not critical
> Payload length: 8
> Transform type: Integrity Algorithm (INTEG) (3)
> Transform ID: AUTH_HMAC_SHA1_96 (2)
> Transform payload
> Next payload: Transform (3)
> 0... .... = Not critical
> Payload length: 8
> Transform type: Pseudo-random Function (PRF) (2)
> Transform ID: PRF_HMAC_SHA1 (2)
> Transform payload
> Next payload: NONE (0)
> 0... .... = Not critical
> Payload length: 8
> Transform type: Diffie-Hellman Group (D-H) (4)
> Transform ID: Group 2 - 1024 Bit MODP (2)
> Proposal payload # 2
> Next payload: NONE (0)
> 0... .... = Not critical
> Payload length: 40
> Proposal number: 2
> Protocol ID: ISAKMP (1)
> SPI Size: 0
> Proposal transforms: 4
> Transform payload
> Next payload: Transform (3)
> 0... .... = Not critical
> Payload length: 8
> Transform type: Encryption Algorithm (ENCR) (1)
> Transform ID: ENCR_3DES (3)
> Transform payload
> Next payload: Transform (3)
> 0... .... = Not critical
> Payload length: 8
> Transform type: Integrity Algorithm (INTEG) (3)
> Transform ID: AUTH_HMAC_SHA1_96 (2)
> Transform payload
> Next payload: Transform (3)
> 0... .... = Not critical
> Payload length: 8
> Transform type: Pseudo-random Function (PRF) (2)
> Transform ID: PRF_HMAC_SHA1 (2)
> Transform payload
> Next payload: NONE (0)
> 0... .... = Not critical
> Payload length: 8
> Transform type: Diffie-Hellman Group (D-H) (4)
> Transform ID: Group 2 - 1024 Bit MODP (2)
> Key Exchange payload
> Next payload: Nonce (40)
> 0... .... = Not critical
> Payload length: 136
> DH Group #: 2
> Key Exchange Data (128 bytes / 1024 bits)
> Nonce payload
> Next payload: Notification (41)
> 0... .... = Not critical
> Payload length: 36
> Nonce Data
> Notification payload
> Next payload: Notification (41)
> 0... .... = Not critical
> Payload length: 28
> Protocol ID: RESERVED (0)
> SPI Size: 0
> Message type: NAT_DETECTION_SOURCE_IP (16388)
> Notification Data
> Notification payload
> Next payload: NONE (0)
> 0... .... = Not critical
> Payload length: 28
> Protocol ID: RESERVED (0)
> SPI Size: 0
> Message type: NAT_DETECTION_DESTINATION_IP (16389)
> Notification Data
> No. Time Source Destination Protocol Info
> 2 0.001877 192.168.30.254 192.168.30.51 ISAKMP IKE_SA_INIT
> Frame 2 (295 bytes on wire, 295 bytes captured)
> Ethernet II, Src: 80:71:1f:b7:b1:85 (80:71:1f:b7:b1:85), Dst:
> Belkin_d0:77:2c (00:17:3f:d0:77:2c)
> Internet Protocol, Src: 192.168.30.254 (192.168.30.254), Dst:
> 192.168.30.51 (192.168.30.51)
> User Datagram Protocol, Src Port: isakmp (500), Dst Port: isakmp (500)
> Source port: isakmp (500)
> Destination port: isakmp (500)
> Length: 261
> Checksum: 0xa6ee [correct]
> Internet Security Association and Key Management Protocol
> Initiator cookie: 593AD8AC6A5DB624
> Responder cookie: 66094DB1161AFEE6
> Next payload: Security Association (33)
> Version: 2.0
> Exchange type: IKE_SA_INIT (34)
> Flags: 0x20
> Message ID: 0x00000000
> Length: 253
> Security Association payload
> Next payload: Key Exchange (34)
> 0... .... = Not critical
> Payload length: 48
> Proposal payload # 1
> Next payload: NONE (0)
> 0... .... = Not critical
> Payload length: 44
> Proposal number: 1
> Protocol ID: ISAKMP (1)
> SPI Size: 0
> Proposal transforms: 4
> Transform payload
> Next payload: Transform (3)
> 0... .... = Not critical
> Payload length: 12
> Transform type: Encryption Algorithm (ENCR) (1)
> Transform ID: ENCR_AES_CBC (12)
> RESERVED TO IANA (7424): <too big (128 bytes)>
> Transform payload
> Next payload: Transform (3)
> 0... .... = Not critical
> Payload length: 8
> Transform type: Pseudo-random Function (PRF) (2)
> Transform ID: PRF_HMAC_SHA1 (2)
> Transform payload
> Next payload: Transform (3)
> 0... .... = Not critical
> Payload length: 8
> Transform type: Integrity Algorithm (INTEG) (3)
> Transform ID: AUTH_HMAC_SHA1_96 (2)
> Transform payload
> Next payload: NONE (0)
> 0... .... = Not critical
> Payload length: 8
> Transform type: Diffie-Hellman Group (D-H) (4)
> Transform ID: Group 2 - 1024 Bit MODP (2)
> Key Exchange payload
> Next payload: Nonce (40)
> 0... .... = Not critical
> Payload length: 136
> DH Group #: 2
> Key Exchange Data (128 bytes / 1024 bits)
> Nonce payload
> Next payload: Certificate Request (38)
> 0... .... = Not critical
> Payload length: 36
> Nonce Data
> Certificate Request payload
> Next payload: NONE (0)
> 0... .... = Not critical
> Payload length: 5
> Certificate type: 4 - X.509 Certificate - Signature
> ------------------
> # ipsec.conf - strongSwan IPsec configuration file
> # basic configuration
> config setup
> plutostart=no
> charondebug="ike 4, knl 4, cfg 4"
> conn %default
> dpdaction=restart
> dpddelay=10s
> auth=esp
> forceencaps=no
> installpolicy=yes
> esp=aes128-sha1-modp1024,3des-sha1-modp1024!
> ike=aes128-sha-modp1024,3des-sha-modp1024!
> ikelifetime=28800s
> keylife=28880s
> rekeymargin=5760s
> keyingtries=1
> leftauth=psk
> rightauth=psk
> keyexchange=ikev2
> mobike=no
> reauth=no
> conn net-net
> left=192.168.30.51
> leftsourceip=192.168.30.20
> right=192.168.30.254
> auto=start
> type=tunnel
> rightsubnet=192.168.1.2/24

======================================================================
Andreas Steffen                         andreas.steffen at strongswan.org
strongSwan - the Linux VPN Solution!                www.strongswan.org
Institute for Internet Technologies and Applications
University of Applied Sciences Rapperswil
CH-8640 Rapperswil (Switzerland)
===========================================================[ITA-HSR]==