40.5. Example of IPSEC configuration

Consider an IPSEC VPN in TUNNEL mode that uses IKE protocol and an ANONYMOUS access, as shown in the following figure.

Figure 40.1. IPSEC configuration example

IPSEC configuration example

[Caution]Caution

The IPSEC connection works ONLY if the LAN, where the PC client is connected to, is different from the LAN of Abilis (e.g. in the previous case if the PC client IP address is belonging to the 192.168.1.0/24 the IPSEC connection doesn't work!).

[Tip]Tip

Interesting chapters:

Section 68.11.1, “How to configure a RAS using IPSEC VPN server”;

Section 68.11.2, “How to configure a RAS using IPSEC VPN server with iPHONE”.

40.5.1. Activating IPSEC parameter on the desired IP resource

Set the IPSEC parameter to YES in the IP resource in which you want to encapsulate IPSEC packets (outgoing traffic). If you want to use the IP-2 resource (ADSL line), type:

[15:54:12] ABILIS_CPX:s p ip-2 ipsec:yes

COMMAND EXECUTED

[16:08:53] ABILIS_CPX:d p ip-2

RES:Ip-2 - IP over PPP (PPP) --------------------------------------------------
Run    DESCR:ADSL_line
       OPSTATE:UP             LOG:NO               STATE-DETECT:NORMAL
       LOWRES:Adsl-1
       IPADD:RETRIEVE                                NEIGH:RETRIEVE
       REDIS:EXT     HIDE:NO         RP:NONE            IPSEC:YES      VRRP:NO
       NAT:OUTSIDE   UPNP:NO         DIFFSERV:NO        DDNS:NO
       OUTBUF:100    OUTQUEUE:FAIR   MTU:1500
       OUTSPL:NO
       INBUF:0                      mru:1500           SRCV:NO
       - TRFA section ---------------------------------------------------------
       TRFA:NO
       - Ppp ------------------------------------------------------------------
       LOG:DS           NRTY3:3         PPP-ENC:RFC2364-VCMUX     RADIUS:NO
       VPI:8            VCI:35
       - Tcp-MSS/Lcp/IpCp -----------------------------------------------------
       TCP-MSS-CLAMP:NO
       maxmru:1500        DNS:NO
       - Authentication -------------------------------------------------------
       USERNAME:abilis
       PASSWORD:********                          LOCAL:CHAP,PAP
       SERVNAME:                                  REMOTE:NONE
       REPEAT:0
RES:Adsl-1 - Not Saved (SAVE CONF), Not Refreshed (INIT) ----------------------
       ------------------------------------------------------------------------
       DESCR:
       LOG:DS      max-vc:1    aal5-max-payload:2100   aal5-payload-rxbuf:30
       usb-rx-bufsize:1728     usb-rx-buf:1            usb-tx-bufsize:3200
[Caution]Caution

To activate the changes made, execute the initialization command init res:ip-2.

40.5.2. Configuration of the Host connections table

Add an IKE Host:

[16:06:36] ABILIS_CPX:a ike host:0 name:user_1

COMMAND EXECUTED

Give the host the following characteristics:

  • local IP used for the VPN: 81.81.81.81;

  • ip resource used for the VPN: ip-2 (ADSL line);

  • no verify of the client's IP address that tries to open the VPN;

  • authentication method: PSK;

  • hash algorithm: MD5;

  • Diffie-Hellman group: MODP1024;

  • encryption algorithm: 3DES;

  • NAT type: inside;

  • Fully Qualified Name identification for the local and remote side.

[16:16:33] ABILIS_CPX:s ike host:0 loc-ip:81.81.81.81 rem-ip:*

COMMAND EXECUTED

[16:16:59] ABILIS_CPX:s ike host:0 auth:PSK hash:MD5 dh:MODP1024 cipher:3DES

COMMAND EXECUTED

[16:17:09] ABILIS_CPX:s ike host:0 side:inside id-type:fqdn fqdn:www.ufficio.it

COMMAND EXECUTED

[16:17:21] ABILIS_CPX:s ike host:0 peer-id-type:fqdn peer-fqdn:www.casa.it

COMMAND EXECUTED

[17:55:47] ABILIS_CPX:d ike host:0

- Not Saved (SAVE CONF), Not Refreshed (INIT) ---------------------------------
Parameter:  | Value:
------------+------------------------------------------------------------------
HOST:         0
NAME:         user_1
LOC-IP:       081.081.081.081
REM-IP:       *
NATT:         SYS
AUTH:         PSK
HASH:         MD5
DH:           MODP1024
CIPHER:       3DES
SIDE:         INSIDE
XAUTH:        NO
XAUTH-USER:
XAUTH-PWD:
MODE-CFG:     NO
KEYING-TRIES: 3
LIFE-TIME:    3600
DPD-ENABLE:   NO
DPD-DELAY:    30
DPD-TIMEOUT:  120
DPD-ACTION:   STOP
ID-TYPE:      FQDN
FQDN:         www.ufficio.it
PEER-ID-TYPE: FQDN
PEER-FQDN:    www.casa.it
-------------------------------------------------------------------------------
[Caution]Caution

To activate the changes made, execute the initialization command init res:ike.

40.5.3. Configuration of the Client connections table

Add an IKE client:

[16:29:57] ABILIS_CPX:a ike cli:0 name:user_1

COMMAND EXECUTED

Give the host the following characteristics:

  • IPSEC negotiation: tunnel mode;

  • ip address of the server: 192.168.1.0/24;

  • ip address of the client: 192.168.200.1/32.

[16:30:15] ABILIS_CPX:s ike cli:0 host-id:0 tunnel:yes

COMMAND EXECUTED

[16:30:33] ABILIS_CPX:s ike cli:0 net-loc:192.168.1.0/24 net-rem:192.168.200.1/32

COMMAND EXECUTED

[16:40:16] ABILIS_CPX:d ike cli:0

- Not Saved (SAVE CONF), Not Refreshed (INIT) ---------------------------------
Parameter:  | Value:
------------+------------------------------------------------------------------
CLI:          0
NAME:         user_1
HOST-ID:      0
RULE:         IPSEC
PASSIVE:      YES
PERMANENT:    YES
TUNNEL:       YES
ESP:          YES
ESP-CIPHER:   3DES
ESP-AUTH:     MD5
AH:           NO
AH-AUTH:      MD5
LIFE-TIME:    28800
PFS:          YES
NET-LOC:      192.168.001.000/24
NET-REM:      192.168.200.001/32
MODE-CFG-DNS: SYS
-------------------------------------------------------------------------------
[Caution]Caution

To activate the changes made, execute the initialization command init res:ike.

40.5.4. Configuration of the Pre-shard Key table

If a PSK authentication is set in the IKE Host table ,you must define a secret key for mutual authentication. In our example type for an ANONYMOUS PSK:

[16:51:32] ABILIS_CPX:a ike psk:0 key:shared_key id-type:anonymous

COMMAND EXECUTED

[16:52:11] ABILIS_CPX:d ike psk
or
- Not Saved (SAVE CONF), Not Refreshed (INIT) ---------------------------------

-------------------------------------------------------------------------------
PSK: KEY:     ID-TYPE:  IP:             FQDN:
-------------------------------------------------------------------------------
0    ******** ANONYMOUS
[Caution]Caution

To activate the changes made, execute the initialization command init res:ike.

40.5.5. Outgoing IP resource for IPSEC packets

Ensuring that outgoing IPSEC packets are routed toward appropriate resource is important.

Add a static route for remote network (in our situation only for host 192.168.200.1/32) towards IP-2 resource (specifying eventually the gateway).

[16:51:32] ABILIS_CPX:a ipr net:192.168.200.1/32 ip:2

COMMAND EXECUTED

[16:52:17] ABILIS_CPX:d ipr

Destination routes and conditional source routes:
+-+-+-+-+--------------------+--------------------+-----------------+----+---+
|B|P|S|H|     NET:/MASK:     |      MASK: or      |       GW: or    |IP: |AD:|
| | | | |                    |   SRNET:/SRMASK:   |      IPLB       |    |   |
+-+-+-+-+--------------------+--------------------+-----------------+----+---+
|*|C| | | 081.081.081.081/32 | 255.255.255.255    |                 |R-ID|  0|
|*|C| | | 192.168.000.000/24 | 255.255.255.000    |                 |   1|  0|
|*|S| | | 192.168.200.001/32 | 255.255.255.255    |                 |   2|  1|
|*|S| | | 000.000.000.000/0  | 000.000.000.000    |                 |   2|  1|
+-+-+-+-+--------------------+--------------------+-----------------+----+---+